Visit the limestone pinnacles in Nauru

Mineral springs that have petrified into white waterfalls of stone above the Oaxaca valleys, with cliff-edge pools you can swim in.

Wind-carved chalk mushrooms and icebergs of rock glowing at sunset — camp overnight under the Sahara stars.

Eroded "moon landscape" near the coast.

Neon sulphur pools, salt flats 125 m below sea level and the Erta Ale lava lake — the hottest inhabited place on Earth.

Waterfall dropping through three natural bridges into a cave shaft.

Otherworldly landscape of limestone chimneys.

Young fissure volcano between spreading tectonic rifts.

Eroded clay badlands a stone’s throw from the city.