The question I often hear is: what equipment do I need for calisthenics?
The basic answer is: none.
Indeed, nature and the urban environment provide all the equipment and apparatus needed for a good workout.
The beauty of calisthenics is that there is always a way to workout your entire body, no matter where you are.
That being said, you can also take your training to the next level and learn many other movements, with very little and affordable equipment.