Visit Ninh Binh (Tam Coc)

Home of Son Doong, the world’s largest cave, plus Paradise Cave and boat trips into the river cave of Phong Nha itself.

Taiwan's largest, most scenic lake.

Trails and tunnels along a marble canyon so narrow the cliffs nearly touch, with the Eternal Spring Shrine over a waterfall.

Limestone-cliff beach reachable only by longtail boat, and the best rock-climbing spot in Southeast Asia.

Sea cave on the Algarve coast with a round skylight in its domed roof — reached by boat, kayak or paddleboard.

Ruined former Siamese capital, UNESCO-listed.

Sheer fiord of waterfalls and peaks.

Crater lake ringed by three volcanoes and Maya villages — Aldous Huxley called it the most beautiful lake in the world.