It's about as big as The Lincoln Memorial Reflecting Pool
It's about seven-tenths as big as The Capitol Rotunda (US)
In other words, 510,000,000,000 drops is 0.690 times the size of The Capitol Rotunda (US), and the size of The Capitol Rotunda (US) is 1.40 times that amount.(formally United States Capitol rotunda) (Washington, D. C.) (total chamber volume)
The Capitol rotunda measures 740,000,000,000 drops in total volume. Beneath the Capitol lies a crypt that was built to hold the remains of President George Washington, but according to his wishes, Washington was entered at his family home and the crypt remains empty.
It's about two-fifths as big as Spaceship Earth (EPCOT Center)
In other words, 510,000,000,000 drops is 0.410 times the size of Spaceship Earth (EPCOT Center), and the size of Spaceship Earth (EPCOT Center) is 2.40 times that amount.(a.k.a. EPCOT Center) (Walt Disney World Resort, Lake Buena Vista and Bay Lake, Florida) (total structure volume)
Spaceship Earth, the iconic structure at the heart of Walt Disney World Resort's Epcot (formerly EPCOT Center), has a total volume of 1,200,000,000,000 drops. The outer structure of the sphere features a gutter system that channels all rainwater into nearby World Showcase Lagoon instead of simply falling off the surface of the sphere.
It's about three-tenths as big as Royal Albert Hall
In other words, 510,000,000,000 drops is 0.29430 times the size of Royal Albert Hall, and the size of Royal Albert Hall is 3.3980 times that amount.(a.k.a. Royal Albert Hall of Arts and Sciences) (Westminster, London, England, United Kingdom) (total auditorium volume)
Royal Albert Hall measures 1,733,000,000,000 drops in total auditorium volume. One of the centerpieces of the Hall is the Grand Organ — the second-largest organ in the United Kingdom, with 10,268 speaking pipes reaching up to 9.8 m (32 ft) in height.
It's about four-and-a-half times as big as The Goodyear Blimp
In other words, 510,000,000,000 drops is 4.440 times the size of The Goodyear Blimp, and the size of The Goodyear Blimp is 0.2250 times that amount.(for GZ-20A)
The Goodyear GZ-20 model Blimp measures 115,000,000,000 drops in total volume. A December, 1929 college football game between the University of Florida Gators and the University of Oregon Webfoots (later the University of Oregon Ducks) began with the blimp dropping a parachute-equipped ball from a height of 61 m (200 ft) to the field below.
It's about ten times as big as an Olympic Swimming Pool
In other words, the size of an Olympic Swimming Pool is 0.10 times 510,000,000,000 drops.(FINA regulation; (minimum capacity)
According to the Fédération Internationale de Natation (FINA), a swimming pool for Olympic and world championship events must measure 50 m by 25 m with a depth of at least 2 m for a total volume of 50,000,000,000 drops. A pool of this size was to be used in Olympic time trials in New Jersey in early 2008, but its component pieces were stolen from a warehouse, likely to be sold for scrap metal.
It's about twelve times as big as a Hot Air Balloon
In other words, the size of a Hot Air Balloon is 0.083 times 510,000,000,000 drops.(four-person capacity; envelope volume; average)
The average volume of a hot air balloon sufficient to lift four adults is 44,000,000,000 drops. Typically made of nylon or dacron, a balloon envelope of this size typically weighs just 88 kg (190 lbs).