21. Second Amendment
There are more guns than people in the United States — about 101 for every 100 people, according to some estimates. The country with the next highest ownership rate is Serbia, where there are 58 guns for every 100 people.
22. German influence
Some 45.2 million Americans identify as ancestrally German, more than any other nationality.
23. Imperial system of measurement
The U.S. is one of only three countries that has not officially switched to the metric system. Liberia and Burma are the other two.
24. Job tenure
The typical wage or salary worker in the U.S. has been with their current employer for 4.2 years.
25. Green currency
The government chose to color U.S. currency green as an anti-counterfeiting strategy. When the color was adopted in the 19th century, cameras could only take black and white photographs, making imitation bills difficult to produce.