Guna Caves, about 8 km from the town centre, are a series of cave passages formed between massive granite boulders, some narrow enough that you have to squeeze through sideways. The forest setting is atmospheric — shola trees, mist, and an almost complete silence — and the caves themselves have the compressed, slightly eerie quality that earned them their original British name of Devil's Kitchen.
Parts of the cave system are closed as the passages can be dangerous, and there have been accidents. The accessible sections are still worth exploring. Combine the caves with a walk through the surrounding shola forest, which is excellent habitat for birds including the Nilgiri flycatcher and various laughing thrush species.