"Civilization III: Play the World, released in 2002, is the first expansion pack for the award winning game Civilization III. Play the World added more civilizations, a new multiplayer feature, new Wonders of the World, new units and new game modes, including: elimination, regicide, and capture the flag.
Play the World (PTW) was generally poorly received. The main feature, multiplayer, was extremely buggy and slow. Most issues were worked out in the second expansion Conquests which led many to regard Conquests as the expansion that Play the World was supposed to have been. However, the new civilizations were generally well received.
One of the major features of Play the World was a turnless game mode, a new concept never used in the previous versions of the Civilization series. The game mode allowed a sort of mixture between turn based and real time gameplay. Although the concept was good on paper, it never actually worked very well and many online players experienced Out of sync issues along with others. Little support from Firaxis and the sundry other issues resulted in the gamemode not returning in Civ IV.
Play the World can also be found on Civilization III: Gold which includes the original Civilization III and Play the World. Civilization III: Play the World is also found on the Civilization III: Conquests expansion."
Source: Wikipedia, "Civilization_III:_Play_the_World," available under the CC-BY-SA License.