The announcement of Cookie's Monster Land (opening in May 2014) means the end of several attractions that have been at Sesame Place since opening day in 1980.
Nets & Climbs:
This opening day attraction is a "maze" of lightweight punching bags in a small sandy area. They will be removed.
Ernie's Bed Bounce:
Big Bird's Nest
To understand the history of these attractions take a look at this image:
Sesame Place was much, much smaller then. The bottom center attractions evolved over time and whatever remained of them in 2006 was eliminated for Elmo's World. The attractions on the right slowly morphed an evolved over time and have all been replaced.
The four main buildings are all still there. Sesame Studio has had drastic changes and now houses Elmo's World Live. Sesame Food Factory has become a traditional cafeteria called Elmo's Eatery. Mr. Hooper's Emporium still operates, but the Computer Gallery has now become another cafeteria named Cookie Cafe.