Very touristy yet totally worth it. The 'Bat cave' is a very old site with a great spiritual significance. As the name suggests, it is a place where you will come across thousands of bats who live there. It is also a mystical place entangled with legends.
8 am - 6 pm
The entrance fee is approimately 15,000 Rp
Info http://www.bali-indonesia.com/attractions/goa-lawah.htm
More information http://www.balitourism.nl/goalawaheng.htm
Address 80761, Indonesia
Coordinates -8°33'5.088" N 115°28'4.788" E