What can bring a priest and a fur trader together? The chance to explore! Jolliet wanted to find a way across North America. Marquette was a priest. He wanted to bring Christianity to the Indians. Marquette and Joliet had heard of a big river that flowed south. They wanted to find it and see where it went.

In 1673, Marquette and Jolliet gathered five men and two canoes. The group started in St. Ignace, Michigan. They paddled to Green Bay, Wisconsin. Then they went up the Fox River. The men had to carry their canoes and supplies to the Wisconsin River.

The Wisconsin River led to the Mississippi River. The group went down the Mississippi as far south as the Arkansas River. They knew the Mississippi River did not go west. They were sure that it did go south all the way to the Gulf of Mexico!

Jolliet and Marquette did not want to go farther south. They might run into Spanish soldiers. They paddled north up the Mississippi to the Illinois River. Marquette and Jolliet had heard it was a shortcut back to Lake Michigan. They entered Lake Michigan near what is now Chicago, Illinois. Jolliet and Marquette had traveled 2,500 miles (4,000 km) by canoe.

Marquette was sick and stayed in Green Bay for a while. Then he went to what is now Illinois to teach the Indians. Jolliet went back to Quebec, Canada. He made money as a fur trader. Later, he made maps and taught navigation.