Chimpanzees are our closest relatives on the evolutionary tree. They are amazingly similar to humans in many ways and seeing them in the wild is an event you will never forget.
There are different subspecies of chimp but the Eastern Chimp that resides through Uganda, Rwanda and Tanzania is the one you are most likely to encounter. Travel to the Congo is not recommended and it is more difficult to see them in West Africa.
The similarities of chimpanzees to humans was brought to our attention by Jane Goodall who studied numerous groups of them at Gombe Stream National Park in Tanzania. Today we know that they communicate, use tools, teach and hunt using distinctly human attributes.
To see chimps in the wild you can visit them in Tanzania or Uganada fairly easily. Both Murchisson Falls and Kibale National Parks in Uganda have groups that are habituated to human presence.
Chimps are much stronger than humans. A male would be over a meter tall (up to 4 feet) and weigh 60 kg (130 lbs) or possibly more. For comparison a normal human male of average build would be 1.65 m at the same weight. The difference is basically all muscle. Chimpanzees are immensely strong in comparison to us.
They normally live in communities led by an alpha male. The ranking of both males and females within the group is important for feeding and for mating privileges.
Chimpanzees are like humans omnivorous. They eat mainly fruits but supplement that diet with meat and insects. Their likeness to humans can be seen in their hunting techniques, where ambushes are set up in advance, and in their use of tools. Chimps use sticks to fish for termites in nests without getting bitten. It is debated whether this technique is learnt by watching or by teaching though most experts believe that it is just imitation that helps younger members of the community learn tool use.