Stonehenge, a massive circular megalithic monument on the Salisbury Plain in southern England, is the most famous of all prehistoric structures. Thought to have been built c. 2000 B.C., it may have been used as an astronomical instrument to measure solar and lunar movements.

The Colosseum (Flavian Amphitheater) of Rome, the largest and most famous of the Roman amphitheaters, was opened for use A.D. 80. Elliptical in shape, it consisted of three stories and an upper gallery, rebuilt in stone in its present form in the 3rd century A.D. It was principally used for gladiatorial combat and could seat between 40,000 and 50,000 spectators.

The pyramids of Giza.

The Great Wall of China (begun c. 214 B.C.), designed specifically as a defense against nomadic tribes, has large watchtowers that could be called buildings. It was erected by Emperor Ch'in Shih Huang Ti and is 1,400 mi long. Built mainly of earth and stone, it varies in height between 18 and 30 ft.

Mount Rushmore (6,000 ft), in South Dakota, became a celebrated American landmark after sculptor Gutzon Borglum took on the project of carving into the side of it the heads of four great presidents. From 1927 until his death in 1941, Borglum worked on chiseling the 60-foot likenesses of Washington, Jefferson, Lincoln, and Theodore Roosevelt. His son, Lincoln, finished the sculpture later that year.

The Taj Mahal (1632–1650), at Agra, India, built by Shah Jahan as a tomb for his wife, is considered by some as the most perfect example of the Mogul style and by others as the most beautiful building in the world. Four slim white minarets flank the building, which is topped by a white dome; the entire structure is made of marble.