Black peppercorn (or black pepper) grows from a flowering vine much like a vanilla bean. Many people are surprised to learn that black pepper is actually a dried fruit. Granted, it's a small fruit (just 5 millimeters in diameter, on average).
Pepper fruit can be three different colors: 1) black pepper, that is cooked and dried unripe fruit, 2) green pepper that is dried unripe fruit, and 3) white pepper that is a ripe fruit seed.
Black pepper is believed to be native to South India, though Vietnam is currently the world's largest producer and exporter of pepper. (Roughly 34% of the world's pepper production comes from Vietnam.)
Pepper, of course, is one of the world's most widely used spices and is most commonly used with salt. The spiciness of black pepper is derived from the chemical "piperine" that it naturally produces.