Here are some things we didn't know about the Great Lakes before starting this year's trip. Hopefully you'll find them interesting as well.

1. Lake Superior contains 3 quadrillion gallons of water (3,000,000,000,000,000). All five of the Great Lakes combined contain 6 quadrillion gallons.

2. Lake Superior contains enough water to hold all of the other four Great Lakes, plus three more the size of Lake Erie.

3. Lake Superior contains a whopping 10% of the world’s fresh surface water.

4. Despite their massive size, the Great Lakes are extremely young by Earth’s standards, only 10,000 years old.

5. There is enough water in the Great Lakes to submerge the U.S. in almost 10 feet of water.

6. Because the Great Lakes have small outlets, it takes a long time for the water volumes in the lakes to replace themselves: Lake Superior (173 years); Lake Michigan (62); Lake Huron (21); Lake Ontario (6); Lake Erie (3)

7. The shoreline of all the Great Lakes combined equals nearly 44% of the circumference of the planet.

8. If not for the the Straits of Mackinac, Lake Michigan and Lake Huron might be considered one lake. Hydrologically speaking, they have the same mean water level and are considered one lake.

9. There are massive sinkholes in Lake Huron that have high amounts of sulfur and low amounts of oxygen, almost replicating the conditions of Earth’s ancient oceans 3 million years ago. Unique ecosystems are contained within them.

10. Lake Michigan is the only Great Lake that is entirely within the borders of the United States. The other Lakes have both U.S. and Canadian shorelines.

11. The largest fresh water sand dunes in the world line the shores of Lake Michigan.

12. The Canadian province of Ontario was named after the lake, and not vice versa.

13. A lake on Saturn’s moon Titan is named after Lake Ontario.

14. A ship leaving from Duluth (on Lake Superior's west side) needs to travel 2,342 miles through the Great Lakes and St. Lawrence Seaway before reaching the ocean, including passing through 16 locks.

15. Babe Ruth hit his first home run as a professional baseball player at Hanlan’s Point Stadium in Toronto. The ball landed in Lake Ontario and is believed to still be there.