Fossae, which mean "ditch" or "trough" in Latin, are prominent features of the surface of terrestrial planets, moons, and asteroids. They often consist of deep, wide depressions, and can be extremely large in size, sometimes thousands of kilometres in length. The shapes of these structures vary from round to linear, and from simple to complex. The presence of fossae on certain bodies has revealed important clues about their formation and evolution. The most common explanation for the formation of fossae is the movement of planetary or satellite tectonic plates. Over long periods of time, this movement can result in the creation of large depressions and fracture systems. This can be seen most clearly on the Martian surface, with famous features like Valles Marineris, one of the grandest canyons in the Solar System. Moreover, certain regions of the Moon's surface also display an abundance of these fracture-like depressions, including the Orientale and Imbrium basins. Fossae can also be created from volcanic activity. When large amounts of lava are discharged from a vent, the superheated material can rapidly cool and solidify, forming a craggy surface feature. This forms where lava is pushed up against adjoining terrain. Regions like the Tharsis region of Mars are full of such lava-formed troughs as a result of volcanic activity. The Cassini Division of Saturn's rings is another excellent example of a large-scale fossa created from eruptions. Ultimately, fossae are some of the most visible and significant features of many planets, satellites, and asteroids, providing valuable clues to scientists searching to uncover the history of these bodies. They play a major role in our understanding of how these objects have changed over time.