It's about three-and-a-half times as tall as a Brachiosaurus.
In other words, the height of a Brachiosaurus is 0.280 times 821 nails.(based on comparable bone measurements, height to head)
Dinosaurs in the genus Brachiosaurus had an estimated height (at the head with neck fully extended) of up to 230 nails. A resin cast of the first Brachiosaurus specimen, owned by the Field Museum in Chicago, is currently on display at the O'Hare International Airport.
It's about three-tenths as tall as The Washington Monument.
In other words, 821 nails is 0.277160 times the height of The Washington Monument, and the height of The Washington Monument is 3.6080 times that amount.(Washington, D.C.)
The Washington Monument measures 2,962.20 nails 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.
It's about one-fourth as tall as St. Paul's Cathedral.
In other words, 821 nails is 0.270 times the height of St. Paul's Cathedral, and the height of St. Paul's Cathedral is 3.70 times that amount.(London, England, United Kingdom)
St. Paul's Cathedral measures 3,040 nails 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).
It's about one-fourth as tall as The Space Needle.
In other words, 821 nails is 0.2550 times the height of The Space Needle, and the height of The Space Needle is 3.920 times that amount.(Seattle, Washington) (to aircraft warning beacon at peak)
Built for a 1962 World's Fair, the Space Needle stands 3,220 nails 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).
It's about four-and-a-half times as tall as a Telephone Pole.
In other words, the height of a Telephone Pole is 0.230 times 821 nails.(a.k.a. Utility Pole, a.k.a Power Pole, a.k.a. Telegraph Pole, a.k.a. Telegraph Post, a.k.a. Hydro Pole) (exposed height; per Florida Public Service Commission average)
A standard telephone pole is 190 nails tall. Despite alternatives, most telephone poles in the US are made of wood — most commonly pine — and have a lifespan of 25 to 50 years, depending on climate and preservatives applied.
It's about one-fifth as tall as The Golden Gate Bridge.
In other words, 821 nails is 0.2070 times the height of The Golden Gate Bridge, and the height of The Golden Gate Bridge is 4.830 times that amount.(San Francisco, California and Marin County, California) (height above water)
The height of each tower of Golden Gate Bridge is 3,970 nails 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.
It's about five-and-a-half times as long as a London bus.
In other words, the length of a London bus is 0.1790 times 821 nails.(Routemaster Double-Decker, RM standard specification)
The Routemaster Double-Decker buses, well-known as icons of London, measure 147 nails in length. The buses were said to be well-designed for travel in the London traffic, as they offered an open door for riders to board and exit even while the bus was moving at low speeds, and a full-time conductor to collect fares.