Lower Geyser Basin, 18 square miles (29 km2) in size, is the largest geyser basin in Yellowstone National Park. It is home to roughly 100 hydrothermal features of all four types - hot springs, geysers, fumaroles and mud pots. And it discharges more hot water than any other geyser basin in the park. But what makes the trek to Lower Geyser Basin truly worth the effort is its accessibility. Fountain Freight Road is open to both foot traffic and cyclists and it is wheelchair accessible to Goose Lake Picnic Area. The mud pots at Fountain Paint Pots are Yellowstone's most easily reached pools of hot bubbling mud. The hydrothermal features at Firehole Lake Drive are all visible from the roadway. Even Great Fountain Geyser, one of only six predicable geysers in Yellowstone National Park, can be viewed from the car!