A large roughtail stingray, Dasyatis centroura, lays on the seagrass-covered seafloor of Turneffe Atoll off the coast of Belize. This reef is part of the massive Mesoamerican Reef System in the Caribbean Sea, the second largest barrier reef on Earth.

A beautiful coral reef, dominated by colorful gorgonians, grows along the edge of the Blue Hole in Lighthouse Reef in the Caribbean Sea. This reef is part of the massive Mesoamerican Reef System, the second largest barrier reef on Earth.

A beautiful coral reef, dominated by colorful gorgonians, grows along the edge of the Blue Hole in Lighthouse Reef in the Caribbean Sea. This reef is part of the massive Mesoamerican Reef System, the second largest barrier reef on Earth.

A beautiful coral reef, dominated by colorful gorgonians, grows along the edge of Turneffe Atoll in the Caribbean Sea. This reef is part of the massive Mesoamerican Reef System, the second largest barrier reef on Earth.

A colorful West Indian starfish, Oreaster reticulatus, crawls over a shallow, sandy seafloor in Turneffe Atoll in the Caribbean Sea. This reef is part of the massive Mesoamerican Reef System, the second largest barrier reef on Earth.

A colorful West Indian starfish, Oreaster reticulatus, crawls over a shallow, sandy seafloor in Turneffe Atoll in the Caribbean Sea. This reef is part of the massive Mesoamerican Reef System, the second largest barrier reef on Earth.

A large roughtail stingray, Dasyatis centroura, lays on the seagrass-covered seafloor of Turneffe Atoll off the coast of Belize. This reef is part of the massive Mesoamerican Reef System in the Caribbean Sea, the second largest barrier reef on Earth.

The interior of the Supai Tunnel along the North Kaibab Trail, Grand Canyon North Rim, UNESCO, Arizona, United States of America

The Coconino Overlook along the North Kaibab Trail at Grand Canyon North Rim, UNESCO, Arizona, United States of America

A well-camouflaged yellow stingray, Urobatis jamaicensis, swims over a shallow seagrass meadow growing within Turneffe Atoll's lagoon in the Caribbean Sea. This reef is part of the massive Mesoamerican Reef System, the second largest barrier reef on Earth

Local man in a Mokoro canoe, Okavango-Delta, Botswana

Locals in a Mokoro canoe, Okavango-Delta, Botswana

The sprawling buttress root system of a rainforest tree. Mary Caincross reserve, Queensland, Australia.

Rolando Garibotti skis with a pack on the Boreas Pass trail which crosses the Rocky Mountains from Breckenridge to Como, Colorado. The trail is part of the Rails to Trails system and follows an old railroad grade. The trail is also part of the 10th Mountain Division Hut System, with a hut called the Section House located along the trail at the top of Boreas Pass. The trail is within Pike-San Isabel National Forest

Damaged petroglyphs, Eagletail Mountain Wilderness, Arizona.