In the enlightenment era of the eighteenth century, many artists and architects looked to classical Greece and Rome as models, spawning the architectural style known as "Neo-Classicism." Featuring white stone, columns, and extensive use of marble, this style is most famous as being used in many of America's government buildings.

The "mock Tudor" style was a revival of the architectural forms and customs popular during the reigns of the Tudor monarchs of England, who ruled from 1485 to 1603. Developed in the late nineteenth century, a period of nostalgia for England's past, mock Tudor, also known as Tudor revival, featured the half-timbered houses and inventive brickwork common to nice houses in England in the sixteenth century, but done in new methods.

The chief challenge in building a bridge across New York's East River was that the depth of the river and the length of the crossing meant that establishing any moorings for the bridge was nearly impossible. The original engineer, John Augustus Roebling, decided to use caissons, watertight retaining structures, which were placed into the East River to allow construction workers to build the bridge. The caissons were so deep that they caused a particular illness known as "caisson disease," a decompression sickness resulting from the pressure inside the caissons.

The Prairie School of Architecture developed in the Midwest in the 1890s as a reaction against the then-popular neo-Classicalism and Beaux-Arts styles. Prairie School Architects sought an authentically American style of architecture that reflected American landscapes. The term, "Prairie School," came about as a comment on the way the broad, plain style of architecture reflected the prairies of the Midwest.

Beaux-arts architecture, named after France's national art school L'Ecole des Beaux-Arts, featured grand structures embellished with baroque details and ornamentation. The Grand Central Terminal in New York was built in 1871 and refurbished in 1913, placing its construction at the height of the Beaux-Arts movement. As such, the railroad station's bronze statuary, ornate grand hall, and finer details make it a key example of the style.

In 1834, the Houses of Parliament burned down in the middle of London, which created the need for a new building to house the government of Great Britain. With rising Victorianism, the commission to build the new House of Parliament went to Charles Barry, who was an early proponent of the Neo-Gothic style. The style hearkened back to the dominant architectural style of the fourteenth to sixteenth centuries, which used grand features such as flying buttresses and ornate windows.

"Beaux-Arts" takes its name from the national art school in France, but describes a separate movement among architects in the United States from roughly 1880 to 1920. The movement was defined by a sweeping neoclassicism that used Baroque motifs, featured a hierarchy of spaces (making grand entryways more important than living areas), added ornate elements like statues and vaultings, and usually employed flat roofs on buildings. The Beaux-Arts style was surpassed by Modernist architecture that valued clean lines and functionality over design details.

Until the late nineteenth century, buildings had serious vertical size restrictions due to the weight placed on them by bricks and other traditional materials. With the introduction of steel, an alloy of iron, new possibilities were available to builders. In particular, the use of steel-frame construction, which built a "sheet" around steel beams, allowed for buildings stretching taller than ten stories.

The Washington Monument, in the center of the National Mall in Washington, D.C., is the world's largest memorial obelisk. Obelisks, four sided pillars that originated with the ancient Egyptians, have long been used in Western culture as memorial markers. The Washington Monument was conceived in the 1840s as more than just the obelisk, but ran into funding problems and was only completed in its simpler form in 1885.