Known to some, new to many, Chiang Mai’s newest (or maybe oldest) natural wonder has had a makeover fit for explorers. Mae Sap Cave – better known as Tham Sai Rung, or Rainbow Cave – has officially reopened after a transformation from dark and dingy hollow to dazzling geological wonder.
Once submerged in water, the dramatic stalactites and stalagmites have frozen mid-drip, a dramatic time capsule millions of years in the making. What is new, however, is the visitor-friendly spruce-up: safe pathways, lighting and a proper chance to admire its natural spectacle without a miner’s helmet.
Inside, you’ll find four chambers – Rainbow, Chapel, Emerald and Diamond – each with its own otherworldly formations. Think towing columns, heart-shaped stones and imaginative shadow casting outcrops that form shapes of animals and ghosts.
The star of the show, though, must be the rainbow of colours that ripple across the walls and ceilings, where layers of white, grey, ochre and brown-yellow limestone bands tell their own story of time.
Stretching 144 metres in length, the cave can be found inside Samoeng’s Khun Khan National Park, some 90 minutes west of Chiang Mai city centre. While far from the city, entrance is just B100, making it the perfect excuse to swap strawberry picking for subterranean sightseeing instead.