Neolithic architecture describes the type of structure built from stone, using stone tools, from about 3500 B.C. to 1500 B.C. An example of this architecture is the structure known as Stonehenge in Salisbury, England. During the Egyptian era, builders used gypsum or other relatively weak compounds to create structures, but by the time Greeks started building, the favored compound was cement -- sand, water and clay bound by lime. Ancient Roman architectural style grew out of its predecessors and is typified by its durability, and by three architectural features: the dome, which will later grace much of Muslim architecture, the arch and the vault. (See References 3) The Roman Colosseum is an example.
The Brooklyn Bridge is an example of Gothic style of architecture, although the era of Gothic architecture stems from the 12th century and is found most frequently in large cathedrals. Tall, thin, ornately decorated and pointed arches are the defining characteristics. Stained glass windows are a feature of this era.
At the same time, Islamic architecture perfects the construction of the dome, a relic of the Roman era, in the building of the Taj Mahal in Agra, India.
Romanesque architectural style was popular in the the Middle Ages and is typified by the continuation of the Roman round arch, thick stone walls, small semi-circular windows and stone carvings. In more northern areas such as England, the style was done on a larger scale and is sometimes called Norman architecture.
St. Paul's Cathedral in London, England, is an example of Renaissance architectural style, featuring a classical theme; other examples include the grand square palaces that became common during this era.
Baroque architecture combined painting and sculpture. The Paris Opera House is an example, as is St. Peter's Cathedral in Rome, where rows of saints are sculpted into roof of the entrance to welcome parishioners.
Since the mid-1800s, architectural styles have grown tremendously. From Art Nouveau -- Tassel House in Brussels, Belgium, is an example -- to Richardsonian Art Deco -- The Chrysler Building in New York is an example -- and many more, the styles have reflected a specific geographic area or historical event.
Modern architecture dared to dip into previously uncharted waters. The CN Tower in Toronto, Canada, is an example. Other examples of modern architecture include the Olympic Games Tent in Munich, the Deconstructionist Modern Wexner Center at Ohio State University and the Corporate Modern Rockefeller Center in New York. Post-modern, The Team Disney Building in Orlando, Florida, is an example. London City Hall is considered High Tech architecture, and the Shaker barn, found in the eastern U.S., is an example of Vernacular architecture.