A big part of my life when I was a monk and now, is meditation. I daily dedicate 2 hours to chanting mantra's at home, in temples and sometimes on rare, fortunate occasions...... in caves.
I can still remember traveling through India in my monastic days and feeling the urge to copy the great sages of old and spend time in "meditation caves". The most intense being in Vrindavana when I shut myself in a purpose built hole in the ground surrounded by complete darkness.
As a practice it's simple. These caves being places where the senses are completely cut off or they are secluded places of simple beauty.
The idea is that you can become absorbed in the meditation of your choosing without the mind dragging us off to the material hullaballoo.
It's something I still do and find of great benefit and recently enjoyed a few hours in this lovely cave in 3 Cliffs Bay, Gower, South Wales.
Give a cave a go. You might find you like it :)