Iturup Island, Russia

The white cliffs of Iturup may not be as famous as those in Dover, yet they are equally stunning to behold. These otherworldly rock formations, which stretch for miles along the island’s northern coast, are the result of frozen volcanic lava that morphed over time into soft pumice stone. Some are topped by a carpet of green, while others form fantastical canyon walls that reach 300 feet in height. Of course, there are plenty of other reasons to visit this wild, windswept island, largest in the Kuril archipelago in the Russian Far East. Iturup boasts 20 volcanoes — nine of which are active — and its landscape is dotted with mineral hot springs, boiling mudpots, and fumaroles. There are numerous waterfalls too, including the 460-foot-high Ilya Muromets Waterfall. Both Soviet and Japanese forces used Iturup as a military outpost; a sprawling underground bunker complex, built by Japan during World War II, was discovered near Sentyabr'skaya Bay in 2021.