This is where visitors board a tram that takes them to the Tier Garten, which is the main part of the zoo. On the way there, it passes by Mirror Lake, Grant's Cabin, and through the Deer Park.
There are bushes in the spaces in between the concrete so its hard to get a super clear photo of it, but it definitely makes it much prettier and offers some sun protection during the days when the line is long (obviously not the day I went).