It was my second time to visit The Heet Cave in Riyadh City. The first time was a few months back at dawn. I was the only one there at that time, and I can tell you that it was a once in a lifetime experience. To be able to go down a hole not less than 50 m deep created by natural earth processes over thousands of years, and be the only one there at that specific time were things I found amazing.
The cave lies about 40 km outside Riyadh, the off-road part is only around a 7 minute drive. Anyone can visit it at anytime, the location is on Google Maps too! I highly recommend the visit to be around the same time I went the first time, at dawn. Absolutely magical!
Here is my experience the second time I went there with a friend.