"Lost cities" refer to ancient urban areas that have been abandoned and often forgotten over time. These cities can be found all over the world, with famous examples including Machu Picchu in Peru and Pompeii in Italy. They provide valuable insights into past civilizations, their cultures, and their ways of life. Many lost cities were rediscovered through exploration or archaeological efforts. Some, like Troy in Turkey, were thought to be mere legends until evidence proved their existence. These sites often attract tourists and researchers, eager to learn about the history and mysteries surrounding these once-thriving communities.