Mahayana Buddhism
Mahayana Buddhism is strongest in Tibet, China, Taiwan, Japan, Korea, and Mongolia.
Mahayana Buddhism is not a single group but a collection of Buddhist traditions: Zen Buddhism, Pure Land Buddhism, and Tibetan Buddhism are all forms of Mahayana Buddhism.
Theravada and Mahayana are both rooted in the basic teachings of the historical Buddha, and both emphasise the individual search for liberation from the cycle of samsara (birth, death, rebirth...). The methods or practices for doing that, however, can be very different.
The Bodhisattva
Mahayana talks a great deal about the bodhisattva (the 'enlightenment being') as being the ideal way for a Buddhist to live.
Anyone can embark on the bodhisattva path. This is a way of life, a way of selflessness; it is a deep wish for all beings, no matter who they are, to be liberated from suffering.