It's about 15,000 times as big as a Polo field.
In other words, 650,000 dunams is 12,956.55880 times the size of a Polo field, and the size of a Polo field is 0.00007718098730 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 50.16764160 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 one-fifteen-thousandth as big as Brazil.
In other words, 650,000 dunams is 0.000076336980 times the size of Brazil, and the size of Brazil is 13,099.810 times that amount.(a.k.a. Brasil, formally the Federative Republic of Brazil, a.k.a. Rep&blica Federativa do Brasil)
Brazil measures 8,514,877,000 dunams in total area. Brazil is the world's fifth-largest country by area and eighth-largest economy (by GDP).
It's about one-fifteen-thousandth as big as China.
In other words, 650,000 dunams is 0.000067729770 times the size of China, and the size of China is 14,764.560 times that amount.(a.k.a. People's Republic of China, a.k.a. 中华人民共和国, a.k.a.中華人民共和國 , a.k.a. Zhōnghuá Rénmín Gònghég) (UN mainland area figure)
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 9,596,961,000 dunams 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.
It's about one-fifteen-thousandth as big as United States.
In other words, 650,000 dunams is 0.000066146480 times the size of United States, and the size of United States is 15,117.960 times that amount.(a.k.a. United States of America, a.k.a. America, a.k.a. USA, a.k.a. US)
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 9,826,675,000 dunams in total area. The United States' economy is the fifth-largest in the world, comprising a quarter of nominal global GDP.
It's about one-fifteen-thousandth as big as Canada.
In other words, 650,000 dunams is 0.00006509980 times the size of Canada, and the size of Canada is 15,361 times that amount.Canada measures 9,984,670,000 dunams 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).
It's about 20,000 times as big as The Lincoln Memorial Reflecting Pool.
In other words, 650,000 dunams is 20,600 times the size of The Lincoln Memorial Reflecting Pool, and the size of The Lincoln Memorial Reflecting Pool is 0.00004850 times that amount.(Washington, D.C.) (pool surface area)
The Lincoln Memorial Reflecting Pool has a water surface area of 31.50 dunams. The Pool has a sloping bottom and extends to 80 cm (30 in) in depth at its center.
It's about one-twenty-five-thousandth as big as Russia.
In other words, 650,000 dunams is 0.0000380156040 times the size of Russia, and the size of Russia is 26,304.9880 times that amount.(a.k.a Российская Федерация, formally the Russian Federation, a.k.a. Россия)
The largest country in the world, Russia measures 17,098,242,000 dunams. Russia spans eleven time zones and holds more forest than any other country in the world, as well as lakes and rivers containing totaling 25% of the world's fresh water supply.