10 most difficult USA riddles

In July 1962 USA conducted a high altitude nuclear test. The explosion at the altitude of 250 miles destroyed 1/3 of all satellites, including Telstar.

Minnesota is a state in the midwestern and northern regions of the United States. Minnesota was admitted as the 32nd U.S. state on May 11, 1858, created from the eastern half of the Minnesota Territory. The state has a large number of lakes, and is known by the slogan "Land of 10,000 Lakes".

President Gerald Ford signed the Metric Conversion Act in1975. It declared the metric system "the preferred system of weights and measures for United States trade and commerce", but permitted the use of United States customary units in all activities. The metrification board was abolished in 1982 by President Ronald Reagan.

Washington, D.C. - 38° 54′ 17″ N, Beijing - 39° 55′ 0″ N, Tbilisi - 41° 43′ 0″ N, Rome - 41° 54′ 0″ N and Tokyo - 35° 41′ 0″ N.

In 1990's U.S. army and marines replaced M16 Rifles with newly designed M4 Carbines which were more compact and comfortable in use.By 2015 M4 was made prime infantry rifle in U.S. weaponry.

Coincidentally, the first European who explored California was a Portuguese on Spanish duty - Cabrillo. However, his country never tried to establish colonies there.

Pittsburgh Steelers has won this trophy six times in 1974, 1975, 1978, 1979, 2005 and 2008.

Of the 27 ratified amendments to Constitution of the USA, only one has been repealed. This was the 18th amendment of 1917 that had introduced the American prohibition. It was repealed in 1933.

In the center of the scene, American General Benjamin Lincoln appears mounted on a white horse. He extends his right hand toward the sword carried by the surrendering British officer, General Charles O'Hara, who heads the long line of troops that extends into the background. To the left, French officers appear standing and mounted beneath the white banner of the royal Bourbon family. On the right are American officers beneath the Stars and Stripes

Balto was a sled dog who led his team on the final leg of the 1925 serum run to Nome, in which diphtheria antitoxin was transported to combat an outbreak of the disease. After the mission's success, Balto and the Norwegian Gunnar Kaasen, who drove the sled, became celebrities.