We enjoyed a packed day today, beginning with a tour of the natural wonders around Lake Myvatn in northern Iceland and ending with a visit to the Arctic Circle. In the morning, we toured the striking geological attractions of the region with stops at a magnificent waterfall, an eerie lava maze, and a pungent and colorful thermal field. After a lunch with a view from the recently constructed Foss Hotel, overlooking Lake Myvatn, we climbed to the top of a volcanic ash crater. After a spectacular dinner on board, and under the light of a midnight sun, National Geographic Explorer visited the island of Grimsey, which touches the Arctic Circle.