Beautiful Mt Nimba is Liberia's tallest peak, 1362m above sea level, and you can feasibly climb it if you have a few days on your hands (it's a rewarding way to beat the heat of Monrovia). You can camp along the way if you have your own equipment, hiking along the peaks. Bring a GPS and warm clothing as it can get misty and very cool at night.
The jumping-off point is the curious town of Yekepa, a 10-hour drive from Monrovia and a Truman Show–esque mining town owned by Arcelor Mittal. The road to Mt Nimba is paved for almost three-quarters of the way to the top; you can drive to the peak using a 4WD. The Noble House Motel is the only sleeping option of note in Yekepa.