1. Flammable ice bubbles: frozen bubbles of methane, trapped beneath Alberta’s Lake Abraham.
2. The Catumbo Lightning, which occurs during 140 to 160 nights a year, 10 hours per night and up to 280 times per hour.
3. Underwater crop circles in the ocean off Japan: created by a male pufferfish in order to woo females.
4. The Great Blue Hole: a large submarine sinkhole off the coast of Belize, over 300m across and 124m deep.
5. Sailing stones in Death Valley, USA: a geological phenomenon where rocks move and inscribe long tracks along a smooth valley floor without human or animal intervention.
6. The Door to Hell, a gas fire in Turkmenistan accidentally ignited by scientists in 1971 and still burning.
Martin Rietze / Via mrietze.com
7. Bioluminescent waves on a beach in the Maldives: Various species of phytoplankton are known to bioluminesce; when washed ashore by the tides, their chemical energy is turned into light energy.