Balinese gardens are usually created in a natural tropical style filled with tropical decorative plants in harmony with the environment. The garden is usually designed according to natural topography and hardly altered from its natural state. Some water gardens however are laid out in a formal design, with ponds and fountains, such as Taman Ayun and Tirtagangga water garden. Bale kambang, which literary means "floating pavilion", is a pavilion surrounded with ponds usually filled with water lilies. Petirtaan is a bathing place, consisting of a series of ponds and fountains used for recreation as well as for ritual purification bathing. An example of petirtaan is Pura Tirta Empul.