The radar tower, painted a seafoam green, is what is left from the Cold War era:  the M-74 Nike Missile Base. Located in Brookfield's Hillcrest Park, it's the ultimate entry to UrbEx and a hometown favorite for many.

Search "Hillcrest Park" in your map app. The tower that you can climb should be obvious as soon as you arrive. Duck underneath the corrugated metal. There should be interior scaffolding of large metal crosses. You can put your feet on the metal bars to climb the interior structure. At the top, emerge through the hole in the cement.

During the Cold War, the United States was peppered with Missile Launch sites, like this one owned by Nike. The tower never contained a missile, but was instead a radar tower for monitoring the area. There was originally a ladder that would take workers to the top, but it was stripped when the site closed down. You can still see the metal sides of where the ladder used to be. 

The actual missile was kept in the large concrete area that is still fenced off. Any extra equipment belonged in the building below this, now known as "The Dungeon." Workers at the site have told me that they aim to convert this building into a small Cold War museum in the next few years. I have yet to see any progress on this.