You knew that Central Park had hills, right? You get to see them all on this run, which traces the "Outer Loop" of the park.
You get a huge downhill about 150m after the start, which gives you a chance to warm up. Good thing: your head up the Great Hill after that, which is the largest single elevation climb on the course, cresting at the 1M marker.
A couple of rolling hills after that, the 2nd one being the highest point in the park just after the 2M marker.
You get a rare flat spot down by the lake, then it's another uphill between the 3M and 5K markers. A couple gentle hills get you through the southernmost part of the course, with a slight uphill to the 4M mark.
At about 4.5M you pass the Boat House and begin ascending "Cat Hill" (see the statue on the rocks, about halfway up), which is a pretty formidable uphill. Recover from that hill as you pass "the Met" museum of art, and mount the gentle uphill to M5.
Now you get about a half mile of flat - the only other flat section in the park - before the last slight rollers that lead to the 6M marker, where you embark on the last slight uphill battle to the turn onto the 102nd St Transverse, just before the finish line.
I guess I tend to mention the uphill sections more than the downhills. They obviously impress me.