Snorkel in the crystal-clear waters of Iceland's Thingvellir National Park and go whale watching on this memorable day trip from Reykjavik. Drive into the stunning park, a UNESCO World Heritage site, and visit Silfra, a natural fissure on a lake where two of the world’s tectonic plates meet underwater. Swim over the tectonic join, and wonder at the extraordinary water clarity and colors. Afterward, drive back to Reykjavik and enjoy a 3-hour cruise to search for minke and humpback whales, porpoises and dolphins in the magnificent setting of Faxaflói Bay.