Dungannon, Ireland, July 26, 2009--A competitor crosses the start/finish line during the Northern Ireland Bog Snorkeling Championships.

The annual event, held in honor of International Bog Day, requires that flipper-outfitted snorkelers swim along a 360-foot (111-meter) stretch of bog without using conventional swimming strokes.

Bogs are acidic wetlands with spongy peat deposits and moss-covered bottoms.