Portions of the large continent of Africa sit in each of the four hemispheres: Northern, Southern, Eastern and Western. While most of the continents are spread across more than one hemisphere, Africa is the only one to encompass all four.
A "hemisphere" is half of a sphere, or half of the Earth. The world can be divided in half in two ways. The equator, located at zero degrees latitude, divides the globe into the Northern and Southern hemispheres, and the prime meridian, located at zero degrees longitude, divides the globe into the Eastern and Western hemispheres. Both the equator and prime meridian run through Africa, which is the second largest continent.