How big is 138 square kilometers?

A Manhattan city block measures about 200 m between the Northeast-Southwest streets by about 60 m between the Northwest-Southeast streets for a total area of about 0.01 square kilometers. There are roughly 2,000 blocks within the city, representing one of the most prolific applications of the city planning grid plan in history.

Trafalgar Square, a public square in London, measures about 0.012 square kilometers. m in total area. At the center of the Square is the 52 m Nelson's Column monument, built in the 1840s.

The "Last Frontier," Alaska measures 1,717,854.3 sq. km in total area. Alaska is home to over 100,000 glaciers — half of the world's total — including the Bering Glacier complex near the southeastern border of Alaska, which covers 5,830 sq. km.

The Palace of Holyroodhouse, the residence of the British Monarch in Scotland, measures about 0.0081 square kilometers, on a total grounds area of about 0.04 square kilometers. Each year, the Palace hosts a Garden Party, serving 8,000 guests from a 150-meter-long buffet table.

Seal Island, named for the tens of thousands of Cape Fur Seals that live there, measures about 0.0081 square kilometers. The large number seals attract great white sharks, who circle the island in a so-called "Ring of Death."

Housing the presidency, the White House occupies six stories and a total of 0.0062 square kilometers of floor space. This space includes 132 rooms, 35 bathrooms, 28 fireplaces, and 3 elevators, as well as a tennis court, bowling alley, movie theater, jogging track, swimming pool, and putting green.

Per NFL rules, a football field should measure 109.728 m (120 yards) long by 48.768 m wide, for a total area of 0.005351215104 square kilometers. Due to a blizzard, the first NFL playoff game in 1932 was held indoors in Chicago Stadium (it was also the first indoor game) on a field measuring just 55 m by 40.0 m, for a total area of 0.0022 square kilometers.

One of the largest homes in the world, Bill and Melinda Gates' home has a total area of 0.004474 square kilometers, including 7 bedrooms, 24 bathrooms, 6 kitchens, 6 fireplaces, a 0.00023 square kilometers gym, a 0.0000900 square kilometers dining room, and a 0.00019 square kilometers library. It was designed by Bohlin Cywinski Jackson, the same architectural firm responsible for the design of one of Apple Inc's flagship stores on Fifth Avenue in New York City.

Brazil measures 8,514,877 sq. km in total area. Brazil is the world's fifth-largest country by area and eighth-largest economy (by GDP).

Mainland China, as measured by the United Nations (excluding China's Special Administrative Regions — Hong Kong and Macau — and disputed territories such as Taiwan, Askai Chin, and the Trans-Karakoram Tract), occupies 9,596,961 sq. km in total area . China is the the most populous country in the world and the third or fourth largest (depending on areas included in the measurement) in total area.

The third or fourth largest country in the world (there is some dispute in how China's total area is measured), the United States measures 9,826,675 sq. km in total area. The United States is the third-most populous country in the world, home to over 300 million people.

Canada measures 9,984,670 sq. km in total area. It is both the second-largest country in the world and one of the most-sparsely populated, in addition to having the longest coastline of any country in the world — 243,000 km (151,000 mi).

Per National Hockey League Official Rules, a hockey rink should measure 60.96 m long by 25.908 m wide with a corner arc radius of 8.5344 m, for a total area of about 0.00151682874 square kilometers. Ice hockey is believed to have developed from field hockey after players began holding games on ice rinks, which had been traditionally used for the sport of curling.

Manchester Cathedral includes a total interior area of 0.001238 square kilometers between the Nave, Chapel, Library, Chapter House, and Rectory. The height of the Cathedral's bell tower is 41.1 m.

The United States Bullion Depository, commonly referred to by the metonym "Fort Knox" (in spite of the fact that the Depository is not located on the Fort proper), measures 32.0 m (105 ft) by 36.9 m (121 ft), for a total area of about 0.00118 square kilometers. The Depository is most famous for housing the largest portion of the national gold reserve, but has also temporarily housed the original US Declaration of Independence, an original copy of the US Constitution, and other important documents, kept there for safe keeping during World War II.