Reuters/Carlos Barria
A man holds an envelope from the U.S. Citizenship and Immigrations Service during a naturalization ceremony at the National Archives Museum in Washington Dec. 15, 2015.
Nearly every one of them would've had to pass a civics test, answering questions about US history, government, and geography.
It's not a huge hurdle, provided you take some time to prepare. The questions are chosen out of a pool of 100 possible queries which are publicly available.
You are asked 10, chosen at random, and have to answer six correctly.
And, you get a second chance if you fail.
Most of the questions aren't that difficult. Like "What is the name of the President of the United States now?"
Also an easy one? "Name one state that borders Mexico."
Just one. There are four states to choose from.
But even if you paid attention in 8th grade US history class, some of these might trip you up. Others will surprise you. Here's a few of the questions, with their answers after each picture.
Remember, you need six correct answers to pass.