Cookie Mountain is an attraction that has been at Sesame Place since opening day in 1980.
Image from YouTube
Sesame Place describes it as:
Why settle for “King of the Mountain” when you can be the “King of Cookie Mountain?” Cheer along your kids as they try to scale this impressive, bright-blue vinyl cone that seems to reach the sky. Watch the all-out effort as they climb, slip and slide their way to the top. And, back down again. (All participants must be 44 inches and under.)
In the early days the vinyl material was a reddish orange color. Today it is in Cookie Monster's more traditional blue color.
Image from Google Street Views