Grutas de Cacahuamilpa

Cacahuamilpa is caving at opera-house scale. The main gallery - carved by ancient underground rivers through a limestone mountain - runs about two kilometres into the rock as a sequence of vaulted salons up to 80 metres high, each dressed in stalagmite scenery accumulated over millions of years: the Goat, the Champagne Bottle, the Throne, the Dawn Hall where a natural skylight once let morning in. A paved, lit walkway makes the full circuit one of the most accessible great caves anywhere; guides pace visitors chamber by chamber, and the acoustics have hosted everything from poetry recitals to full orchestral concerts. The old graffiti near the entrance includes signatures of nineteenth-century notables who toured by torchlight. Below the show cave, the Chontalcoatlan and San Jeronimo rivers still run through their own wild caverns - full-day guided river traverses for the adventurous - and emerge at the Dos Bocas springs downstream.

What you actually see

• The great salons - chambers to 80 metres under vaulted stone.
• The named formations - thrones, goats and bottles in flowstone.
• The lit walkway - two kilometres of easy underground walking.
• The river caves - wild traverses beneath the tourist route.

When to go

Year-round inside - the cave keeps its own climate; morning tours meet the fewest groups. River-cave traverses run in the dry season only, November to April.

Honest expectations

Entry is guided-group only on a fixed schedule, and the commentary is Spanish; the walkway is long but gentle. Colored floodlighting divides opinion. The return climb to the entrance gains a sweaty hundred metres.

Nearby

Taxco's silver lanes are half an hour uphill; the Dos Bocas spring pools and Ixcateopan's Cuauhtemoc shrine extend the circuit.