It's about as big as Alcatraz.
(a.k.a. The Rock) (California)
Alcatraz Island measures 89 dunams. It is known a part of the Golden Gate National Recreation Area, and has historically served as a lighthouse, fort, military prison, and — most famously — a federal prison.
It's about one-and-one-fifth times as big as Buckingham Palace.
In other words, the size of Buckingham Palace is 0.83 times 89 dunams.(a.k.a. Buckingham House) (Westminster, London, England)
Buckingham Palace, the official residence of the British monarch, contains about 77 dunams of total floor space. The palace was first inhabited by Queen Victoria in 1831, although after the death of her husband in 1861, the Queen endeavored to spend as little time there as public opinion would allow.
It's about four-fifths as big as Ellis Island.
In other words, 89 dunams is 0.802 times the size of Ellis Island, and the size of Ellis Island is 1.25 times that amount.(Jersey City, New Jersey and New York City, New York)(now officially part of the Statue of Liberty National Monument)
Ellis Island, home of the Ellis Island Immigration Station, is 111 dunams in total area. Nine-tenths of the island were artificially created after the New York-New Jersey borders had already been defined, leading to a sovereignty dispute which was settled by the US Supreme Court in 1998.
It's about two-thirds as big as The Pentagon.
In other words, 89 dunams is 0.645 times the size of The Pentagon, and the size of The Pentagon is 1.55 times that amount.(a.k.a. United States Department of Defense Headquarters) (Washington, D.C.) (total floor area)
The Pentagon, the world's largest office building, contains a total floor area of 138 dunams. Built during World War II, the designers compensated for the steel rations then in effect by using 310,000 cu. m of concrete in the construction efforts.
It's about one-and-seven-tenths times as big as Windsor Castle.
In other words, the size of Windsor Castle is 0.59 times 89 dunams.(Windsor, England) (total site area)
One of the official residences of the British monarch, Windsor Castle measures about 53 dunams. It is the largest inhabited castle in the world and is also the oldest in continuous use, having been occupied since it was built by William the Conqueror about 900 years ago.
It's about one-and-three-fourths times as big as a Polo field.
In other words, 89 dunams is 1.7740519 times the size of a Polo field, and the size of a Polo field is 0.563681367 times that amount.(for field polo) (United States Polo Association rules; unboarded side maximum)
An outdoor polo field must measure 274.32 m in length and 146.304 m to in width for a total playing area of up to 50.1676416 dunams. Polo traces its origins to an Iranian (then Persian) war game from the 5th Century, which was played with as many as 100 players per side.
It's about two-fifths as big as Grand Central Station.
In other words, the size of Grand Central Station is 3 times 89 dunams.(formally Grand Central Terminal, a.k.a. Grand Central, a.k.a. GCT) (New York City, New York) (total terminal area). Grand Central station, the largest train station in the world by platform count, measures 200 dunams in total area. The large flag which was suspended from the concourse ceiling following the September 11th 2001 terrorist attacks measures about 0.07 dunams.