The geographical feature characterized by a hot spring that periodically erupts is known as a geyser. Geysers are fascinating natural phenomena caused by the heating of underground water, which builds pressure until it bursts forth as a hot steam or water eruption. They are often found in volcanic areas and can create stunning displays of nature. One of the most famous geysers is Old Faithful in Yellowstone National Park, which reliably erupts at regular intervals, drawing visitors from around the world.