
It's about oneandonetenth times as tall as The Sears Tower.
In other words, 21,000 inches is 1.01 times the height of The Sears Tower, and the height of The Sears Tower is 0.990 times that amount.
(a.k.a. Willis Tower) (Chicago, Illinois) (to antenna peak)The Willis Tower rises to 20,700 inches to the top of its tallest antenna. The bathrooms on the 103rd floor are said to be the highest in the western hemisphere at 16,200 inches.
It's about as tall as The Ostankino Tower.
In other words, the height of The Ostankino Tower is 1 times 21,000 inches.
(a.k.a. Останкинская телебашня) (Moscow, Russia) (to spire)The Ostankino Tower stands 21,000 inches to its spire. The tower has been the tallest structure in Europe since its construction in 1967 and was, at at that time, the only freestanding structure taller than 20,000 inches.
It's about as tall as The CN Tower.
In other words, the height of The CN Tower is 1.0374 times 21,000 inches.
(a.k.a. La Tour CN, a.k.a. Canadian National Tower, a.k.a. Canada's National Tower) (Toronto, Canada) (to spire)The CN Tower measures 21,785 inches tall at its spire. Used only in emergencies and for charitable climbing events, the 2,579step staircase to the top is the longest metal staircase in the world.
It's about oneandonetenth times as tall as The Taipei 101 (skyscraper).
In other words, 21,000 inches is 1.05 times the height of The Taipei 101 (skyscraper), and the height of The Taipei 101 (skyscraper) is 0.9520 times that amount.
(a.k.a. Taipei Financial Center, a.k.a. 台北101, a.k.a. 臺北101) (Xinyi District, Taipei, Taiwan) (to spire)The Taipei 101 reaches 20,000 inches to its spire. The tower itself is said to be the style in world's tallest sundial, with the circular area of the adjacent Millennium Park acting as the sundial's face.
It's about oneandonetenth times as tall as The Shanghai World Financial Center.
In other words, 21,000 inches is 1.08 times the height of The Shanghai World Financial Center, and the height of The Shanghai World Financial Center is 0.9260 times that amount.
(上海环球金融中 上海環球金融中心, Shànghǎi huánqiú jīnróng zhōngxīn) (a.k.a. SWFC) (Shanghai, China) (to spire)The Shanghai World Financial Center is 19,400 inches tall to its roof. It is home to both the world's highest hotel (on its 79th through 93rd floors) and the world's tallest observation deck (on its 100
It's about ninetenths as tall as a Canton Tower.
In other words, 21,000 inches is 0.870 times the height of a Canton Tower, and the height of a Canton Tower is 1.10 times that amount.
(a.k.a. Guangzhou TV & Sightseeing Tower, a.k.a. 广 州 电 视 观 光 塔) (Guangzhou, China) (to spire)The Guangzhou TV & Sightseeing Tower stands 24,000 inches to its spire. Initially described as holding the record for the tallest Ferris wheel in the world, the ride at the top of the tower is actually an observation carousel; cars complete a trip around the topfloor track about every halfhour.
It's about oneandonefifth times as tall as The Petronas Twin Towers.
In other words, 21,000 inches is 1.180 times the height of The Petronas Twin Towers, and the height of The Petronas Twin Towers is 0.84750 times that amount.
(a.k.a. Menara Berkembar Petronas, a.k.a. Petronas Towers) (Kuala Lumpur, Malaysia) (to spire)Each of the Petronas Towers stands 17,790 inches to their spires. Holding the record as the tallest buildings in the world from 1998 to 2004, the towers continue to hold the record for the deepest foundation barrettes — up to 4,528 inches deep. 
