One of the interesting-but-vanished historical sites of Minneapolis was the Wonderland Amusement Park on east Lake street. An area equal to four city blocks was walled in and dedicated to the park, which was filled with a variety of delights for visitors. On opening day, May 27, 1905, 70,000 people traveled the trolley rails out Lake street to the park. Only one building has survived from that park... the home of the Infant Incubators, a most unusual exhibit of premature infants in incubators. The exhibit was intended to illustrate how modern science could save premature infants who would otherwise have died. The building that housed the infants is now an apartment building (photos below), on the SE corner of 31st street and 31st avenue. No other remnants of the park remain.
click on this image for a much larger version

Here are some marvelous old postcard images of Wonderland, from the collection of Charles D. Test.
click on the images for larger versions.

In this very old photo of Longfellow School, which was built in 1915 (3 years after Wonderland was demolished),
we can happen to see a 2-story building at the far left. That is the Premie hospital, just across 31st avenue.
If this photo had been taken a few years earlier, it would have shown the wall of Wonderland,
and Longfellow wouldn't have been there. Notice the unpaved street

This is a 2005 view of that same building.

In this view of the building, we can verify, from the rather unusual placement of windows on the end,
that this is the same building shown in the school photo.

Articles containing more information:
An article about the Incubator Baby Shows by Hannah Lieberman
A City Pages article