1. From Reykjavik: Silfra Fissure Snorkeling Half-Day Trip
Undergo a unique underwater experience by snorkeling in the Silfra fissure on a half-day tour from Reykjavik. Frequently rated as one of the world's top 10 dive sites, Silfra offers up to 100 m (300 ft) of underwater visibility. Admire views of Iceland's stunning landscape as you ride from Reykjavik to the heart of Thingvellir National Park, a UNESCO-listed World Heritage Site. Snorkel in this location for 1 hour with your guide, before returning to the warmth of the tour van and heading back to Reykjavik. The cold waters melt off a glacier 50 km (30 miles) away, and make their way through lava fields to beautiful Thingvellir Lake. Although the chilly waters are too cold to support much in the way of marine life, Iceland's Silfra crack runs down between the American and European continental plates and offers amazing underwater views.