Visit Yellowstone National Park in the USA
Steam drifts across a boardwalk, a pool holds colours that look almost mineral and somewhere beyond the road a bison changes the traffic plan. Yellowstone repeatedly makes the ground, weather and wildlife feel less settled than the map suggests. The park holds more than 10,000 hydrothermal features and a large share of the world's active geysers, alongside canyons, forests and major wildlife habitat. Two or three days can connect Old Faithful, a thermal basin, the Grand Canyon of the Yellowstone and time spent watching from a safe distance. Check current roads, weather and eruption information, reserve scarce accommodation or campsites early and allow long driving times. Stay on boardwalks, never touch or enter thermal water, keep at least 100 yards from bears and wolves and 25 yards from other wildlife, and use pull-outs rather than stopping in the road. Count it complete after seeing a working thermal basin and experiencing the wider park without leaving the routes that protect you and the landscape. Add it if the chance to watch geology happening in real time is worth planning around a very large wild place.