The playground was the result of a long design review (if you went to the Mercer Island Community Center at a certain time last year you could see all the proposals) and a lot of money from the Mercer Island Preschool Association.
From the Mercer Island gov website:
After months of careful planning, construction is scheduled to begin this Friday May 17th at the Luther Burbank Park Playground. As part of the 2013-2014 Capital Improvement Program, the aging play structure will be replaced with new equipment including a zip line, climbing web, improved slides, merry go-round, and safety surfacing. Private donations and a public-private partnership with Mercer Island Preschool Association made this project a reality.
A zip line! When I was a kid…