There's an unusual place in the northern part of Kuala Lumpur - Batu Caves. They have quite a large size (ceiling height up to 100 meters) and are located in the city. The entire complex of caves is an active Buddhist temple. In January, during religious festivals, they are visited by about 1.5 million pilgrims.
Please note that you'll need to pass 272 steps before you reach the largest cave. The first wooden staircase was built in 1920. And since 1892, the Taipusam Tamil festival is held in a cave.
There are lots of monkeys near the caves and a small terrarium for children.
Admission to all main caves is free, there's a guided tour to the Dark Cave. The caves are open daily from 7 am to 7 pm.
Getting there: The caves are located 14 kilometers to the north from the city center. Taxi from the center costs $6-8 depending on the traffic. Ask the driver to wait for you. We went there and back by the KTM Komuter train from the central station KL Sentral. The Batu Caves stop is the final station of the "Port Klang Route - Batu Caves" line, and it is located right next to the caves, which is quite convenient. We bought the tickets at the railway ticket office (~$1.5), travel time was about 30 minutes. The timetables can be found at the official website (in the left menu), but generally the trains run every 30 minutes.
Buses U6 (get off at APM) and U10 (get off at Jalan Sri Batu Caves 5) run to the caves. At the official website you can view information about their stops, althouth the website is not user friendly. When boarding the bus, better ask the driver to stop at the desired station.