Along with lounging in the Blue Lagoon's waters, visitors can relax in two steam baths, rest in a sauna, or be "massaged" by a waterfall. For a wholly unique experience, book an in-water treatment. Your massage therapist will help you shimmy onto a foam raft, cover you with a blanket, and knead away tension as you float on the water.
Icelandic fun fact #5: Almost all Icelanders speak perfect English. Their own language is so well-preserved that the average citizen can read and understand their ancestors' 13th-century sagas.