People have come to what is now the United States in lots of different ways. The first people who came here walked. Isn't that amazing? You can't walk to America any more. The land bridge they used is underwater. When these first Americans came from Asia, the world was much colder. Lots of water was frozen in giant sheets of ice that covered a lot of the land. Humans and animals were able to go back and forth between Asia and America.
The next group of people to find the New World traveled by sailing ships from Europe. They were explorers at first. They eventually became settlers. The trip from Europe to North and South America was difficult and dangerous. Even so, people just kept coming.
When steamships were invented, the trip from Europe became easier and safer. Many more people came to the Americas from Europe, Asia, and Africa. They came to make a better life for themselves and their families. Most of these people were poor. Usually they were able to find work.
Today, people usually fly to the United States across the ocean. The trip doesn't take that long, often ten hours or less. The planes they fly in are comfortable, and once they get here, traveling on the ground is simple. Surprisingly, the people who come to the United States today come for many of the same reasons that they did before.