Fill in all the gaps with figures and numbers, then press "Check" to check your answers.





















Yellowstone National Park

Yellowstone National Park is huge, encompassing acres. In , Congress made it the world’s first national park. It is hidden within one of the most remote places in the lower 48. It is bigger than Rhode Island and Delaware combined. Right here, no road in any direction for miles. A canyon, miles long. rivers dissect the wilderness. Sweeping grasslands, more than enough to sustain Yellowstone’s bison. Yet, for all you can see, the real story behind Yellowstone is in what you can’t see. Here, just underground, lies one of the world’s largest volcanoes. It reveals itself at the surface in menacing ways, with mudpots that belch toxic gas, and fumerols that hiss with acid vapour. Super heated pools of water, steam vents and geysers, attract some tourists a year. Few understand that Old Faithful won’t be faithful for ever. And one day, the volcano below may erupt. Under Yellowstone’s surface, just miles down, is a massive cauldron of magma, its total volume enough to fill more than Lake Michigans. It’s been years since it last erupted, and no one knows if or when it will explode again.
Yellowstone is also home to species of mammals. Elk and bison are just two of them. And Yellowstone is home to one of the greatest wildlife reintroduction success stories: the grey wolf. Wolves here were wiped out in the s under an old predator eradication programme. They were reintroduced in . And the wolves have an influence on Yellowstone’s elk and bison populations. By preying on elk and bison, they keep the populations of these herbivores at a stable level, which in turn helps keep Yellowstone’s ecosystem healthy. Life continues on Yellowstone’s surface and the molting earth beneath seemingly moves with a life of its own, and present day visitors can witness the geological splendour of its changes.