Nov. 2, two days before the park closed to car traffic for the winter, we set out to walk the round-trip 2.8 miles (4.4 km) from Old Faithful to Morning Glory Pool. This area is near the edge of the large caldera that makes up much of Yellowstone National Park and has a large concentration of geysers, some that erupt on a regular basis. the volcano at Yellowstone had massive eruptions 2 million, 1.3 million and 642,000 years ago. Today I read in the newspaper scientist have discovered the caldera has bulged 3" this year.