Flexi Says: Sinkholes generally form where underlying limestone rock dissolves in groundwater. The rock becomes weaker and eventually caves in. Any soil, pavement, or structures overlying the rock may cave in as well. In some parts of the world, sinkholes are very common because of the geology. For example, sinkholes are found all over the state of Florida. They are a natural part of the landscape of the state. In 1981, a gigantic sinkhole opened up in the middle of the city of Winter Park, Florida. Some measures, such as report changes in depressions, cracks on the ground surface to local authorities, locate and fill the cavity at high-risk areas, etc, can be taken by civil engineers to prevent sinkholes.