Wonders are monumental buildings and events in the history of the world and are constructed using Great People. They are the method of scorekeeping and winning Eras through culture. Players can access the Wonders screen via the main taskbar. In Civilization World, there are two different kinds of Wonders.
Great Wonders - Buildings and projects which provide powerful and persistent bonuses to all members of the Civilization where the Wonder is built.
Wonder Events - Special events which provide a one-time bonus to a Civilization. Wonder Events do not count when measuring for a Culture Era victory.
On the wonders screen, the three available Wonder Events will appear on the first line. Any available Great Wonders will be displayed below them.
You can win a Culture Victory for an era by constructing a number of Great Wonders. Early in the game, a Civilization can win with as few as three Great Wonders, with each era after that requiring more Great Wonders to win, up to a maximum of 21.
Building a Wonder
Wonders are built by combining different kinds Great People. If a player has a Great Person of the kind needed for the wonder, he or she may click on the empty slot in that Wonder to contribute their Great Person towards that Wonder. Once all of the Great Person slots are filled, the Wonder is immediately built in that Civilization.
Each player may contribute only one Great Person towards a Wonder. There are several exceptions: The Culture Minister of a Civilization has the power to contribute any number of people to a single Wonder, and members of a civilization with the United Nations Wonder or the Freedom of Speech civic can contribute any number of people to a single Wonder. Additionally, the King may contribute multiple people.
If there are no Great Wonders available to build, your Civ will have to research more technology to unlock them. For example - The Stonehenge Wonder becomes available after the Civ discovers the Literacy Technology.
Each time a Great Wonder is built, another civilization may replace it by building a "better" version. Replacing a Great Wonder will cost at least one more Great Person than was required to build it originally, up to a maximum of six. Note that a civilization cannot replace their own Wonder with a better version.
Many ancient and medieval Great Wonders will become obsolete with the discovery of advanced technology. Once a Great Wonder has become obsolete, it is no longer possible to build a replacement. Instead, the civilization that held it at the time it became obsolete will continue to hold it until the end of the game -- the only way to gain control of obsolete Great Wonders is to conquer the civilizations that own them. Obsolete wonders still provide their bonus to their owner.These are the list of technologies which make some Wonders obsolete. It is strongly advised that your civilization should get those Wonders before completing the technology or else, they can not be rebuilt anymore.