An island located in the Detroit River is home to a ton of history and lots of fun things to do right outside the city.

One of the most interesting things to do there is paying a visit to Belle Isle Park, which is a slice of natural splendor without having to leave the concrete jungle. This historic area is also home to the oldest aquarium in the entire United States.

Belle Isle Aquarium’s old architecture is stunning, and to add up, the place stands next to the sparkling glass domes that make up the conservatory.

The front has an intimidating facade with intricate carvings, and on the inside, you're met with an unexpected burst of color.

The ceiling is covered in green tiles that seem to glow. You can almost feel the guests of 100 years ago walking along with you.

Opening on August 18, 1904, this was the third-largest aquarium in the U.S. at the time. Today, it's the oldest aquarium in the entire country.

Parking and admission are free. However, a recreation passport is required to enter the island in a car. You can purchase those at the entrance or get the pass added to your license plate when you renew your registration. Hours of operation are Friday through Sunday from 10 a.m. to 4 p.m.

Under the aquarium is a speakeasy that was in business during the Prohibition Era, a Crain’s report states. As if this place wasn't cool enough, there's an underground club that used to let people party their hearts out.

The speakeasy is only open to the public during certain special events, so make sure to look out for an opportunity to check it out.

Outside of the aquarium itself, there is a koi pond that is filled with fish annually. In the past, Belle Isle has had a springtime celebration for them.

This article has been updated since it was originally published on February 25, 2020.