A thermal spring is a natural water source that emerges from the ground, heated by geothermal energy. This heat comes from the Earth's interior, where molten rock and hot gases can raise the temperature of underground water. As a result, thermal springs often have higher temperatures than regular springs, sometimes reaching up to 100 degrees Celsius or more. These springs can be found in various locations around the world, often in areas with volcanic activity, such as Yellowstone National Park in the United States or Iceland. Thermal springs are not only fascinating geological features but also attract visitors for their potential health benefits and unique ecosystems.