How long is 40 chains?

The total race length of the Kentucky Derby run at Churchill Downs is 100 chains. First run in 1864, the Kentucky Derby is one of the oldest continuously-running sporting events in America, almost two years older than the Westminster Kennel Club Dog Show

The QE2 has a total length of 14.60 chains. During its voyaging lifetime from 1969 through 2008, it travelled more than 477,000,000 chains, the furthest cumulative distance by any ship in modern history.

The roller coaster The Beast is 111.50 chains in length. On its twenty-fifth year of operation in 2004, The Beast was awarded the Landmark Award by the American Coaster Enthusiasts as a historically significant roller coaster.

The total race length of the Belmont Stakes run at Belmont Park is 120 chains. It was during the 1974 Belmont Stakes that Secretariat set an America Grade 1 stakes record in winning by a distance of about 3.7575760 chains

The roller coaster Steel Dragon 2000 is 123.20 chains in length. It is one of only two operating "Gigacoasters" (meaning its height is between 4.5450 chains and 6.045 chains) in the world, having a height of 4.8220 chains.

From the steps of the Capitol Building to the Lincoln Memorial, the National Mall is 100 chains. On December 4th, 2008, the entirety of the Mall was declared open to the public for the first time in American history in anticipation of the estimated two million visitors to the Mall for the inauguration of President Barack Obama on January 20th, 2009.

The height of each tower of Golden Gate Bridge is 11.30 chains above the surface of the San Francisco Bay. One of the key designers of the bridge, Charles Ellis, had no engineering degree when he began working on the project, but would later go on to write what became a standard textbook on structural engineering, and would ultimately be forced to complete his calculations on the bridge by working without pay for five months.

Built for a 1962 World's Fair, the Space Needle stands 9.150 chains tall. With a track-and-wheel design inspired by railroad mechanics and a precisely-configured balance, the restaurant near the top of the space needle requires just a 1.5 hp motor to rotate at speeds of about 0.053 kph (0.033 mph).

St. Paul's Cathedral measures 8.650 chains to its peak. The southwest tower of the Cathedral contains the bell known as "Great Paul," which is the largest bell in Great Britain at 15,000 kg (16.5 tons), outweighing the more iconic Big Ben bell by about 3,000 kg (3 tons).

The Washington Monument measures 8.41540 chains tall, with some discrepancy due to the fact that the Monument's base is slightly below the surrounding ground. Interrupted in its construction by the American Civil War, it was almost 36 years between groundbreaking and the completion of construction.

The Hollywood Walk of Fame is approximately 190 chains. Gene Autry, most famous as the singer of "Back in the Saddle Again" and as the writer and singer of "Here Comes Santa Claus," is the only entertainer to have a star in every category — film, television, recording, radio, and theater. One of Autry's stars is also one of only two stars which have been stolen from the Walk and never recovered.

The Singapore Flyer has a height of 8.20 chains. Based on recommendations from Feng Shui masters, the wheel was re-engineered to spin in the opposite direction five months after it began operating.

The seventeenth hole on Pebble Beach Golf Links is a par 3 measuring 8.05 chains from the blue tee. This hole was the site of professional golfer Jack Nicklaus' 1972 U.S. Open win, which included a 1-iron shot that bounced off the hole's flag and resulted in a birdie.

The rectangular oval course of the Indianapolis Motor Speedway is 200 chains. While famous for its automotive racing, the first motorsport held at the track was a series of motorcycle races in August, 1909 — a little less than two years before the inaugural Indianapolis 500 race was run.

The tri-oval course of the Daytona International Speedway, upon which the NASCAR Daytona 500 is run, is 200 chains in length. Although the tri-oval design is said to allow for greater visibility during the race, the real reason for the then-unique design was that plot available for construction of the track was only 350 acres and could not accommodate a traditional oval layout of appropriate length.