Travian is a real time strategy browser game set in a world with several (thousand) players.
The game is centered on building villages, form alliances and going to war. In order to build buildings you need four resources: wood, clay, iron, and grain. The raw materials are extracted from fields and mines, which can continuously be upgraded to increase production. Similarly, you can build many different buildings, each with their own special task.
The game is played on servers which have a limited lifetime. Late in the game it is possible to build a wonder of the world and whichever alliance builds this first is declared the winner. At this point the server ends, so it can be restarted later.