Building Knowledge:

Fascinating Facts About Architecture & Construction

The Incas considered bridges so sacred that anyone who tampered with one could be put to death. Among their most impressive engineering achievements were the chacas, or rope bridges, which spanned deep gorges and rushing rivers. Constructed from plaited grasses woven into cables as thick as a man's body, some stretched as far as 175 feet. Building one of these remarkable bridges required the efforts of as many as 1,000 people, and many remained in service for more than 500 years.

The 60-story John Hancock Tower in Boston has long been associated with one of the most unusual engineering mysteries in skyscraper history. Soon after the building was completed in 1972, its massive 4-by-11-foot glass windowpanes began unexpectedly popping out and shattering on the streets below. In an effort to solve the problem, the John Hancock Mutual Life Insurance Company replaced all 10,344 windows with 400-pound panes of half-inch tempered glass. Yet the windows continued to fail. Although engineers eventually identified design and thermal stress issues and replaced the windows, the tower's early glass failures remain one of the most famous construction challenges in modern architecture.

A bridge built in Lima, Peru, around 1610 was constructed using mortar mixed with the whites of 10,000 eggs instead of water. Appropriately named the Bridge of Eggs, it is said to still stand today.

The Column of Trajan, erected in A.D. 113 to commemorate Emperor Trajan's victories over the Dacian tribes, features a continuous spiral frieze nearly three feet wide and 620 feet long, depicting more than 2,500 human figures along with hundreds of horses, boats, wagons, and pieces of military equipment. The column still stands today, rising approximately 128 feet high. Inside is a spiral staircase leading to a viewing platform. Trajan's ashes were originally placed in a chamber at its base.

The Empire State Building contains approximately 10 million bricks.

Japanese farmers have long found creative uses for rice byproducts. After removing the edible kernels, rice hulls are mixed into a paste, molded into brick-shaped blocks, and used to construct homes. These unique dwellings are sometimes referred to as "houses of rice skin."



Many homes in the rural regions of Nepal are constructed from a mixture of cow dung, mud, sand, and clay. This traditional building material provides effective insulation and is readily available.

The Escorial, the famous royal palace and monastery outside Madrid, Spain, was designed in the shape of a gridiron in honor of Saint Lawrence, who was martyred by being roasted on one.

It takes approximately 15 to 20 minutes to walk completely around the Pentagon.

The base of the Great Pyramid of Giza is large enough to cover about 10 football fields.

According to the Greek historian Herodotus, it took approximately 20 years and the labor of 400,000 men to construct this monumental achievement.

In the mid-16th century, Toyotomi Hideyoshi, often called Japan's "Peasant Ruler," ordered all the swords in the nation to be collected and melted down. The metal was used to create an enormous statue of Buddha in 1586. More than 50,000 artisans worked for over six years to complete the monument. Tragically, just 10 years after its completion, an earthquake destroyed the statue, leaving no trace of it behind.

The Leaning Tower of Pisa leans at an angle of approximately 4 degrees after extensive stabilization work. It reopened to visitors in 2001 after more than a decade of restoration and remains one of the world's most famous architectural landmarks.

Contrary to popular belief, the Great Wall of China is not the only man-made structure visible from space. In fact, astronauts have reported that it is generally difficult to see with the naked eye from low Earth orbit. Many large cities, airports, bridges, and other human-made features are more readily visible under favorable conditions.