Swim through Iceland’s Silfra fissure — it’s called the “Big Crack” — and you can place one hand on the Eurasian tectonic plate, the other on that of North America. Dive Iceland offers day tours from Reykjavik to the tundra of Thingvellir National Park, 31 miles east of the capital. A small staging-area platform leads to the narrow underwater corridor with three major hollows: Silfra Hall, Silfra Cathedral and Silfra Lagoon. The water is 39.2 degrees F at its warmest. In between the jagged rock walls, the glacier-fed water unfurls visibility, stretching to 330 feet by Hossi Elefsen’s estimates. Says the Dive Iceland instructor, “This visibility gives you the feeling of floating in outer space like an astronaut.”
When to Go: Year-round
Operator: Dive Iceland is a PADI Five Star Dive Center in Reykjavik, offering day trips to nearby attractions, including Silfra.
Price Tag: The day trip to Silfra costs $295, and includes transportation, equipment, park fees and a guide.