1. Dirty thunderstorms, aka volcanic lightning, occur when lightning is produced in a volcanic plume.
Martin Rietze / Via mrietze.com
They look like the entrance to Hell!
Carlos Gutierrez / UPI Photo / Landov
2. Oh wait, here’s The Door to Hell, a gas fire in Turkmenistan accidentally ignited by scientists in 1971 and still burning. Oops.
Flickr: flydime / Creative Commons
3. Flammable ice bubbles: frozen bubbles of methane, trapped beneath Alberta’s Lake Abraham.
Emmanuel Coupe / Getty Images
4. The Catumbo Lightning, which occurs during 140 to 160 nights a year, 10 hours per night and up to 280 times per hour.
commons.wikimedia.org / Creative Commons
5. Christmas Island’s Red Crabs: Each year an estimated 43 million land crabs migrate to lay their eggs in the ocean.
Imago / Barcroft Media
Authorities close most of the island’s roads during the migration, which normally takes at least a week.
6. Monarch butterflies: The eastern North American population is notable for its southward late summer/autumn migration from the USA and Canada to Mexico, covering thousands of kilometers.
Flickr: lunasinestrellas / Creative Commons
No individual butterfly lives through the whole migration. Female monarchs lay eggs and their offspring continue the migrations.
7. Surreal spiderwebs: Fleeing torrential floodwaters near Wagga Wagga, Australia, thousands of spiders cover fields with cobwebs.
8. Namibia’s mysterious Fairy Circles: Studies suggest that a sand termite is responsible for their creation.
Norbert Juergens / University of Hamburg
9. Underwater crop circles in the ocean off Japan: created by a male pufferfish in order to woo females.
Yoji Ookata / NHK / Via ookatayouji.amaminchu.com
10. Spherical boulders in New Zealand: exhumed from the mudstone enclosing them by coastal erosion.
Flickr: chris_gin / Creative Commons
11. The Great Blue Hole: a large submarine sinkhole off the coast of Belize, over 300m across and 124m deep.
12. The Black Sun: Huge flocks of up to 50,000 starlings form in areas of the UK just before sundown during mid-winter. They are known as murmurations.
Flickr: 27770620@N02 / Donald Macauley / Creative Commons