Visit Hierve el Agua

Rhyolite mountains streaked orange, green and pink, with a natural hot river to soak in after the walk — the start of the Laugavegur trail.

Waterfall dropping through three natural bridges into a cave shaft.

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

White travertine terraces and pools.

Loop past geysers, falls and rifts.

Drop into a limestone sinkhole of crystal-clear fresh water on the Yucatan, where the Maya saw the entrance to the underworld.

Swim at the very edge of Victoria Falls.

Terraced cascades amid mango groves near Banfora.