Phu Pha Man National Park

The park is a block of limestone hills on the Khon Kaen and Loei border, and its best-known event happens every evening at Tham Khang Khao, the bat cave, in the cliff face. Somewhere in the low millions of wrinkle-lipped free-tailed bats roost inside, and around dusk they leave to feed - not in a scatter but as a continuous ribbon that pours from the cave mouth and winds across the sky in a coiling stream, taking twenty to forty minutes to clear. Watching from the ground below the cliff is free of any effort: the column passes overhead. The colony's insect consumption is enormous and of real agricultural value in the surrounding rice country. Elsewhere the park has caves with prehistoric paintings and skeletal remains, waterfalls and forest. Timing is the whole thing - arrive well before sunset, since the emergence starts on its own schedule and does not wait.

What you actually see

• The bat emergence - millions leaving the cliff cave in a continuous ribbon at dusk.
• The duration - twenty to forty minutes for the column to clear.
• The cliff - the limestone face the cave opens from.
• The other caves - prehistoric paintings and remains elsewhere in the park.

When to go

Any evening, arriving thirty to sixty minutes before sunset. November to February for the most comfortable conditions. The emergence happens year-round but numbers vary.

Honest expectations

Timing is unforgiving - arrive late and it is over. Mosquitoes at dusk are serious. Facilities at the viewing area are minimal. The bats are high overhead; binoculars help, cameras struggle in the light.

Nearby

Phu Wiang is north; Chum Phae and Khon Kaen are east.