Milwaukee is full of unexpected surprises at every turn. Outsiders don’t realize that our little city is full of fun, festivals, and flavors, but once you see it you won’t soon forget. The same goes for this little piece of history that’s hiding beneath our city streets. In a world that’s compromised of so much water, it’s hard to believe that entire bodies of it can exist unbeknownst to us, but Milwaukee has been hiding a shoreline other than Lake Michigan for centuries.

Before Milwaukee was the concrete jungle we know and love that it is today, much of the city was swampland.

When settlers arrived in what is now the downtown "East Town" area, there was a few feet of water wherever you stood. What we know as Wisconsin Avenue was a narrow channel that drained into Lake Michigan, and beside it sat Lake Emily. Locals would bring their horses down to the pond-like lake to water them, and kids splashed in the shallow lake.

It’s often debated whether the forgotten "lake" was actually a lake or a reservoir made to stop overfill.

Being such a small body of water, it's likely that Lake Emily froze completely every year. It's hard to say whether our hidden lake was actually a lake or a large pond, but much information is lost to history even to this day.

However, Lake Emily still exists.

The shallow lake sits below the original Northwestern Mutual headquarters building on Cass and east Wisconsin Avenue. The building was built directly on top of the lake, and the shores of Lake Emily are still going strong within the basement of the building.

To construct a building on top of the little lake, virgin wood was brought down from up north. Each wooden piling—and there are 3,000 of them—had to be drilled into the bedrock, and capped with concrete to build on top of. Construction started in 1905 and didn’t finish until 1912.

Twenty years later, an addition was added to the north side of the building with 4,000 more pilings!

Though the north building can’t be seen from above anymore, its basement is still used for everything from storage to making baked goods. The walls in these buildings are incredibly thick at four feet and nine inches. Even though there’s no building to top the basement, it’s one of the safest places in downtown Milwaukee were there ever an emergency.

To this day, Lake Emily is still being preserved.

Employees of the NML building check on the water levels in the basement, and add water when needed. The building was made with Lake Emily in mind, and all of the rainwater flows into the system below.

We might not know who Emily was, but she’s still going strong beneath our city streets.

Did you know that there’s an entire lake underground in Milwaukee? What other hidden secrets does our city hold? We won’t tell!