The Gambia has no migrating wildebeest, giraffes or any of the large animals commonly associated with Africa. However without leaving your hotel you can see a breathtaking variety of bird life, in addition to monkeys and lizards. Baboons and crocodiles can be seen nearby and then far up the river, hippos.
As the gasses collect in the magma chamber, the pressure rises. It is possible for the pressure to rise so much that the chamber cannot contain the magma and it erupts explosively. Some US Parks that have active volcanoes formed as the result of subduction related processes are: 1  Crater Lake National Park, OR.
At subduction zones, volcanoes are created on the overriding plate as melt from the subducting plate rises up through the mantle and crust. See the map below. Tectonic map showing active volcanoes, plate boundaries, and the Ring of Fire.