View of Anchor Cruiser Blucher and Astrup Fearnley Museum of Modern Art, Aker Brygge, Oslo, Norway, Scandinavia, Europe

Detail of anchor coral tentacles (Euphyllia sp.) growing on a reef in Indonesia. This area is known for its high marine biodiversity.

Wooden sailing boat anchored in clear turquoise water off Cala Granara, Spargi Island, La Maddalena Archipelago National Park, Sassari, Sardinia, Italy, Mediterranean, Europe

View of boats in the bay at Kalami with Corfu Town in background, Corfu, Ionian Sea, Greek Islands, Greece, Europe

View of boats and harbour in Thassos Town, Thassos, Aegean Sea, Greek Islands, Greece, Europe

Bleached coral damaged by water warming and anchor, Dominican Republic

The National Geographic Endeavour at sunset in the Lemaire Channel near the Antarctic Peninsula.

Miami Harbor, Florida, America

Diver at Anchor Hawse Hole at Bow of USS Saratoga, Marshall Islands, Bikini Atoll, Micronesia, Pacific Ocean

Diver at Anchor Hawse Hole at Bow of USS Saratoga, Marshall Islands, Bikini Atoll, Micronesia, Pacific Ocean

Thorny Seahorse (Hippocampus histrix) clinging to small anchor, Makadi Bay, Hurghada, Egypt, Red Sea, Africa

Graphic structure of polyps of the Anchor Coral (Euphyllia ancora), Selayar Island, West coast, South Sulawesi, Indonesia, Java Sea, Indian Ocean

Anchor Bay, Mendocino County, California, USA

Matt Edney jumps off the swim platform of a catamaran while at anchor in the British Virgin Islands on Sunday, January 8th, 2012

Kinsale, County Cork, Ireland

Inishowen Maritime Museum, Greencastle, County Donegal, Ireland

Diver at Anchor Hawse Hole at Bow of USS Saratoga, Marshall Islands, Bikini Atoll, Micronesia, Pacific Ocean

Diver at Anchor Hawse Hole at Bow of USS Saratoga, Marshall Islands, Bikini Atoll, Micronesia, Pacific Ocean

Grey triggerfish (Balistes capriscus) attracted by an anchor crawling on the seabed. Fish of the Canary Islands, Tenerife.