Discover Northern Ireland's hexagonal rock formations
View naturally wave-shaped rock formation
Limestone arches over hidden pools.
Drop into a limestone sinkhole of crystal-clear fresh water on the Yucatan, where the Maya saw the entrance to the underworld.
Jagged coral pinnacles of the interior.
Walk through a forest of razor coral pinnacles to a ladder that drops into a hidden sandy oasis with palm trees between the cliffs.
Waterfall dropping through three natural bridges into a cave shaft.
Young fissure volcano between spreading tectonic rifts.
Neon sulphur pools, salt flats 125 m below sea level and the Erta Ale lava lake — the hottest inhabited place on Earth.
Bubbling grey cones on the Caspian steppe — half the world’s mud volcanoes are here.
Wind-carved chalk mushrooms and icebergs of rock glowing at sunset — camp overnight under the Sahara stars.
Drift by boat beneath a cave ceiling lit by thousands of glowworms.
Mineral springs that have petrified into white waterfalls of stone above the Oaxaca valleys, with cliff-edge pools you can swim in.
The highest tides on Earth, best watched among the Hopewell Rocks flowerpot stacks.
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