Time Out says
Batu Caves is a limestone hill, which has a series of caves and cave temples, located in Gombak district, 13 kilometres (8.1 mi) north of Kuala Lumpur, Malaysia. Made up of three main caves and several small ones, the "Temple Cave" or "Cathedral Cave" is the best known of the caves.
The cave is one of the most popular Hindu shrines outside India, dedicated to Lord Murugan. It is the focal point of Hindu festival of Thaipusam in Malaysia. To reach to the temple cave, you must make your way up a tedious 272 rock stairs. Do watch out for monkeys.
As featured in Time Out KL's 101 things to do in KL