is different from Theravada
Buddhism in that a Mahayana monk will not search for nirvana
for himself, but will attempt to help others reach nirvana. The theory is that the world would be best off if I
could take all the suffering upon myself. The Dalai Lama
is one of these.
Mahayana Buddhism has many more different factions than does Theravada Buddhism. It is also more complex. The two main teachings that set it apart from Theravada Buddhism are the bodhisattva doctrine, (you can only become enlightened if you do so to help other), as described above, and the existence of meditational deities--personifications of Buddhist ideals on which you focus during meditations.
As with Theravada Buddhism, it is about 2000 years old, although it is sometimes sed to be the younger of the two forms. There is no real evidence for this.
See the Four Noble Truths and specifically The Eightfold Path for instructions on how to reduce suffering.
See also: Karma
Compare to Theravada Buddhism.