This adventurous tour is your chance to go cave exploring and snorkeling in one incredible day. On this day trip from Reykjavik, visit Iceland's Gjábakkahellir cave and the Silfra fissure, both located in the UNESCO World Heritage-listed Þingvellir National Park. Marvel at unique sights and discover the depths of some of Iceland's most stunning natural wonders as you explore a mysterious cave and snorkel in a pristine, dream-like underground pool. Your friendly, knowledgeable guide will make sure that you have an unforgettable experience.After pickup from your Reykjavik hotel, head by comfortable mini-coach in less than an hour to Þingvellir National Park, a UNESCO World Heritage Site, to begin your amazing Iceland adventure. Listen to a brief safety introduction, and then follow your guide to explore the dark, mysterious world of the lava field under Þingvellir National Park. Enter Gjábakkahellir and discover the marvels that volcanic activity has created; the cave is a perfect example of an Icelandic lava tube and is situated in one of the most active volcano areas in the world due to the riffs that enabled lava to surface ages ago. See shield volcanoes, which are products of lava flows that left impressive layers of scenery over the years. After exploring the cave for an hour and a half, dine on a packed lunch before moving on to the blue depths of Silfra.Head to the Silfra fissure, one of Iceland’s most-hidden treasures. Admire the otherworldly scene of the rift, famous for its heavenly shades of crystal-clear blue water, and feel weightless as you float lazily for two hours down the current. Then, put on your snorkel gear and continue exploring the dream-like underground pool. Your guide will lead you to the most scenic spots as you swim between the North American and Eurasian tectonic plates.When your incredible journey is over, the coach will take you back to your hotel in Reykjavik.Please note: In the winter Leiðarendi cave will be explored in the first part of this tour.