At 437m deep and 50m high, Siddha Gufa is said to be the largest cave in Nepal. Its cathedral-like interior is full of stalactites and stalagmites, not to mention hundreds of bats, which whistle overhead. Trekking here and back from Bandipur is a popular (if muddy) half-day trip, including a 1½-hour hike each way. Consider hiring a guide from Bandipur's Tourist Information Centre. Alternatively, you can hike up to the cave from Bimalnagar on the Prithvi Hwy, which only takes 45 minutes.
From Bandipur, follow the signs starting from the north end of the village. These take you along a dirt path running north over the edge of the ridge, turning right at the obvious junction. The stone path is slippery, so mind your step. Compulsory guides (Rs 200) await you at the cave’s entrance. Torches (flashlights) are also available for hire.