A bi-color flabellina nudibranch, Flabellina bicolor, crawls across a black sand seafloor in Alor, Indonesia.

A vibrant nudibranch, Chromodoris sp., crawls across a coral reef in the remote, tropical islands of Raja Ampat, Indonesia.

A colorful flamboyant cuttlefish, Metasepia pfefferi, crawls across the sandy seafloor in Lembeh Strait, Indonesia.

A greater blue-ring octopus, Hapalochlaena lunulata, crawls across a coral reef in Komodo National Park, Indonesia. There are several blue-ring octopus species and all of them are extremely venomous.

View across the still waters of the harbour, early morning, Porto Cervo, Arzachena, Sassari, Sardinia, Italy, Mediterranean, Europe

View across wooded landscape to the Roccia dell'Orso (Bear Rock), evening, Capo d'Orso, Palau, Sassari, Sardinia, Italy, Mediterranean, Europe

Panoramic view across turquoise sea to Arbatax and Capo Bellavista, Santa Maria Navarrese, Baunei, Nuoro, Sardinia, Italy, Mediterranean, Europe

View across clear turquoise water to rocky headland at northern end of the Spiaggia Rosa, Budelli Island, La Maddalena Archipelago National Park, Sassari, Sardinia, Italy, Mediterranean, Europe

View from shore across the calm turquoise waters of Cala Napoletana, Caprera Island, La Maddalena Archipelago National Park, Sassari, Sardinia, Italy, Mediterranean, Europe

Panoramic view across River Etive towards snow-covered mountains including Buachaille Etive Mor, Rannoch Moor, near Fort William, Highland, Scotland, United Kingdom, Europe

Glastonbury Tor seen across the marshes of Ham Wall National Nature Reserve, one of the Avalon Marshes nature reserves, near Glastonbury, Somerset, England, United Kingdom, Europe

High voltage power lines stretching across Johnson Canyon in the Kaibab National Forest of Arizona. Viewed from the historic abandoned Johnson Canyon Railroad.

Snake Temple (Mwe Paya) at sunset, Dalah, across the river from Yangon (Rangoon), Myanmar (Burma), Asia

Kerala boatman ferrying local villagers across the backwaters in wooden dugout canoe, Kumarakom, Kerala, India, Asia

View across cloister lawn to the twin western towers of Durham Cathedral, Durham, County Durham, England, United Kingdom, Europe

Small boat heading towards the waterfront across the Bay of Kotor, Perast, Kotor, UNESCO World Heritage Site, Montenegro, Europe

View across the Caribbean Sea from beach, Pigeon Island National Landmark, Gros Islet, St. Lucia, Windward Islands, Lesser Antilles, West Indies, Caribbean, Central America

View north across Munnar tea estates to the Western Ghats and 2695m Anamudi, highest peak in south India, Munnar, Kerala, India, Asia

View across harbour to the historic citadel, the Bastion de l'Etendard prominent, Bonifacio, Corse-du-Sud, Corsica, France, Mediterranean, Europe

View across the harbour from quayside, early morning, colourful boats moored at jetty, Bonifacio, Corse-du-Sud, Corsica, France, Mediterranean, Europe

Autumn across the marshy open moors of Dartmoor, Gidleigh Common, near Chagford, Dartmoor National Park, Devon, England, United Kingdom, Europe

Autumn across the marshy open moors of Dartmoor, Gidleigh Common, near Chagford, Dartmoor National Park, Devon, England, United Kingdom, Europe

Sunset view from Walney Island across the Irish Sea towards the distant Walney Offshore Wind Farm, Cumbrian Coast, Cumbria, England, United Kingdom, Europe

Finsthwaite, High Dam, English Lake District, Furness Peninsula, Cumbria, UK. View across High Dam.

View across the Duddon Estuary towards the Coniston mountain range and the Lake District National Park, Furness Peninsula, Cumbria, England, United Kingdom, Europe

Road across a volcanic crater, with small buildings in the distance, inland on the island of Sao Vicente, Republic of Cape Verde Islands, Atlantic, Africa

A West Indian starfish (Oreaster reticulatus) crawls slowly across a sand and seagrass seafloor in Turneffe Atoll, Belize. This part of Central America is well known for its clear waters and beautiful coral reefs.

A West Indian starfish (Oreaster reticulatus) crawls slowly across a sandy seafloor in Turneffe Atoll, Belize. This part of Central America is well known for its clear waters and beautiful coral reefs.

A beautiful nudibranch (Halgerda batangas) crawls across the black sand seafloor in Lembeh Strait, Indonesia.

Looking across the wilderness of Tierra del Fuego from the Cordon Martial mountains, Patagonia, Argentina, South America

A long, dusty road stretches across the vast landscape of Song Kol Lake area, Kyrgyzstan

Wildebeests and zebras on the move at dusk across the dusty landscape of Amboseli National Park, Kenya, East Africa, Africa

Looking across Dubrovnik's terracotta tiled rooftops, Dubrovnik, Croatia, Europe

View of the Alexander Nevsky Cathedral and 2018 World Cup football stadium in Nizhny Novgorod across the Volga River, Russia, Europe

View across Victoria Harbour, from Hong Kong Island to Kowloon, seen from Victoria Peak, Hong Kong, China, Asia

View across harbour to the historic citadel, the Bastion de l'Etendard prominent, Bonifacio, Corse-du-Sud, Corsica, France, Mediterranean, Europe

View across harbour to the town and citadel, hills of the Cap Corse peninsula beyond, St-Florent, Haute-Corse, Corsica, France, Mediterranean, Europe

Autumn across the marshy open moors of Dartmoor, Gidleigh Common, near Chagford, Dartmoor National Park, Devon, England, United Kingdom, Europe

Sunset view from Walney Island across the Irish Sea towards the distant Walney Offshore Wind Farm, Cumbrian Coast, Cumbria, England, United Kingdom, Europe

Reflections from Sandscale Haws Nature Reserve, view across the Duddon Estuary towards Black Combe, Cumbrian Coast, Cumbria, England, United Kingdom, Europe

Himalayan village with farm houses spread across the endless terraces, Lang Tang National Park, Nepal, Asia

View across the calm water of Jokulsarlon glacial lagoon towards snow-capped mountains and icebergs bathed in winter morning light, at the head of the Breidamerkurjokull Glacier on the edge of the Vatnajokull National Park, South Iceland, Iceland, Polar Regions

A storm rolling across Grand Canyon near the Sinking Ship formation, viewed from Coronado Ridge, Grand Canyon National Park, UNESCO World Heritage Site, Arizona, United States of America, North America

Panoramic view across marina from South Pointe Park, dusk, Downtown Miami in background, South Beach, Miami Beach, Florida, United States of America, North America

An atmospheric dusk view across the village of Salcombe and the Kingsbridge estuary, on Devon's south coast, Devon, England, United Kingdom, Europe

View across the Grand Canal from Punta della Dogana towards the Palazzo Ducale and Piazza San Marco, Venice, UNESCO World Heritage Site, Veneto, Italy, Europe

Wildebeests and zebras on the move at dusk across the dusty landscape of Amboseli National Park, Kenya, East Africa, Africa

A view across the Cairngorms from the top of Creag Dubh near Newtonmore, Cairngorms National Park, Highlands, Scotland, United Kingdom, Europe

Looking out across the Cairngorm in winter to Angels Peak, 1258m, and Braeriach, 1296m, Scotland, United Kingdom, Europe

View of Sava River across to St. Michael's Cathedral in the historical center, Belgrade, Serbia, Europe

View across calm sea to the white limestone cliffs of the Scala dei Turchi, Realmonte, Porto Empedocle, Agrigento, Sicily, Italy, Mediterranean, Europe

The Old Town from across the river Daugava, Riga, Latvia, Baltic States, Europe

Fog gliding across the sea and up onto Highway 1, California, United States of America, North America

View from the Pa'rus Trail across woodland to the Towers of the Virgin, autumn, Zion National Park, Utah, United States of America, North America

Autumn across the marshy open moors of Dartmoor, Gidleigh Common, near Chagford, Dartmoor National Park, Devon, England, United Kingdom, Europe

View across the Duddon Estuary towards the distant Scafell mountain range and the Lake District taken from Sandscale Haws Nature Reserve, Cumbria, England, United Kingdom, Europe

Sunset from Sandy Gap on Walney Island, view towards the distant Black Combe across the Irish Sea, Duddon Estuary and Cumbrian Coast, Walney Island, Lancashire, England, United Kingdom, Europe

Matsumoto-jo (Matsumoto Castle), three-turreted donjon built in 1595 in contrasting black and white, surrounded by a moat with access across ornate red bridges, Matsumoto, Nagano Prefecture, Central Honshu (Chubu), Japan, Asia

View from rocks across the clear turquoise waters of Cala Corsara to the pink granite headland of Punta Rossa Corsara, Spargi Island, La Maddalena Archipelago National Park, Sassari, Sardinia, Italy, Mediterranean, Europe

Chartres Cathedral across the River Eure, Chartres, Eure-et-Loir, France, Europe

The Burj Khalifa Dubai, elevated view across Sheikh Zayed Road and Financial Centre Road Interchange, Downtown Dubai, Dubai, United Arab Emirates, Middle East

View across Lake Pukaki to Mount Cook (Aoraki) and neighbouring mountains, Mount Cook National Park, UNESCO World Heritage Site, Southern Alps, South Island, New Zealand, Pacific

Gondola and San Giorgio Maggiore Church across Basino di San Marco, Venice, UNESCO World Heritage Site, Veneto, Italy, Europe

Hiking across the Rainbow Mountain chain in the Andes, Peru, South America

View across Victoria Harbour, from Hong Kong Island to Kowloon, seen from Victoria Peak, Hong Kong, China, Asia

Climber looks across the Tsaranoro Massif, southern Madagascar, Africa

View across the tranquil Merced River below Swinging Bridge, autumn, Yosemite Village, Yosemite National Park, UNESCO World Heritage Site, California, United States of America, North America

View across the Venetian Harbour, sunset, the Koules Fortress reflected in water, Iraklio (Heraklion), Crete, Greek Islands, Greece, Europe

Sundial and skyline across Lake Union, Gas Works Park, Seattle, Washington State, United States of America, North America

A railway viaduct across the River Tamar, at Calstock, on the Devon-Cornwall border, in east Cornwall, England, United Kingdom, Europe

High voltage power lines stretching across Hell Canyon east of Paulden, located in the Prescott National Forest, Arizona, United States of America, North America

A shoal of Blue-striped Snappers (Lutjanus kasmira) swims across a tropical coral reef, in Gaafu Dhaalu atoll, The Maldives, Indian Ocean, Asia

People walking home across Nam Cuong sand dunes, Ninh Thuan, Vietnam, Indochina, Southeast Asia, Asia

View from hillside across bay to the ruined Genoese watchtower at Pointe de la Parata, Ajaccio, Corse-du-Sud, Corsica, France, Mediterranean, Europe

View of The Pond, one of seven bodies of water in Central Park located near Grand Army Plaza, across Central Park South from the Plaza Hotel, New York City, United States of America, North America

Beautiful puruple sunrise colour gradient spread across mountain chains, including Dorje Lakpa, Himalayas, Nepal, Asia

View across the lake to the castle, former home of Catherine of Aragon, first wife of Henry VIII, Leeds Castle, Kent, England, United Kingdom, Europe

Mount Cook (Aoraki) viewed across Lake Pukaki, Mackenzie Country, South Canterbury, Canterbury, South Island, New Zealand, Pacific

Church of St. Peter and the Old Town at dusk from across the river Daugava, Riga, Latvia, Baltic States, Europe

Horse-drawn buggy tearing across plain at dusk, Bagan (Pagan), Myanmar (Burma), Asia

Iguazu Falls, Brazil, looking across to Argentinian falls, UNESCO World Heritage Site, Brazil, South America

View across rocks to Mount Williamson and the Sierra Nevada, Alabama Hills National Scenic Area, Lone Pine, California, United States of America, North America

The Assiniboine Park Pavilion seen across the Duck Pond skating rink at Assiniboine Park, Winnipeg, Manitoba, Canada, North America

Rail bridge across the River Rhine at Rheinfall (Rhine Falls), near Schauffhausen, Switzerland, Europe

View from palm-fringed beach across Soufriere Bay to Petit Piton, evening, Soufriere, St. Lucia, Windward Islands, Lesser Antilles, West Indies, Caribbean, Central America

View across colourful crowded beach to the rugged slopes of Pizzo di Sella, San Vito Lo Capo, Trapani, Sicily, Italy, Mediterranean, Europe

View across rolling volcanic landscape to the summit of Mount Etna, UNESCO World Heritage Site, at sunrise, Taormina, Messina, Sicily, Italy, Mediterranean, Europe

Leopard walking across the savannah in the Maasai Mara National Reserve, Kenya, East Africa, Africa

High angle view of Lake Como with a ferry boat travelling across the lake, Lombardy, Italian Lakes, Italy, Europe

View by night across colourful lake to the illuminated facade of the Bellagio Hotel and Casino, Las Vegas, Nevada, United States of America, North America

View across lake to replica Eiffel Tower at the Paris Hotel and Casino, Bellagio fountains in foreground, Las Vegas, Nevada, United States of America, North America

View across the town of Street towards Glastonbury Tor on a misty autumn morning, Somerset, England, United Kingdom, Europe

Double Rainbow across Loch an Tairbeairt towards Leac Easgadail, Isle of Harris, Outer Hebrides, Scotland, United Kingdom, Europe

View across tranquil harbour to the citadel, sunrise, typical fishing boat in foreground, Ajaccio, Corse-du-Sud, Corsica, France, Mediterranean, Europe

View across marina to the town and coastal hills of the Balagne region, L'Ile-Rousse, Haute-Corse, Corsica, France, Mediterranean, Europe

Autumn across the marshy open moors of Dartmoor, Gidleigh Common, near Chagford, Dartmoor National Park, Devon, England, United Kingdom, Europe

Autumn across the marshy open moors of Dartmoor, Gidleigh Common, near Chagford, Dartmoor National Park, Devon, England, United Kingdom, Europe

Sunset view from Walney Island across the Irish Sea towards the distant Walney Offshore Wind Farm, Cumbrian Coast, Cumbria, England, United Kingdom, Europe

Sunset view from Walney Island across the Irish Dea towards the distant Walney Offshore Wind Farm, Cumbrian Coast, Cumbria, England, United Kingdom, Europe

View across the polluted Bishnumati River in Kathmandu, Nepal, Asia