Prayer wheels were plentiful at the Monkey Temple. They completely encircle the Stupa and are found located around other structures that adorn the Monkey Temple. Traditionally, the mantra Om Mani Padme Hum is written on the wheels. Spinning the wheel is supposed to have the same benefits as reciting the mantra out loud. According to the lineage texts on prayer wheels, prayer wheels are used to accumulate wisdom and merit (good karma) and to purify negativities (bad karma).
As is done by the believers, I made a spinning round around the main stupa. I didn’t do this because I was seeking good karma rather than as thanks for a wonderful life. I also did this in the pouring rain in the hopes the falling drops could cleans me of any bad karma hanging on to my body.