The $475 million cost of the park, originally planned to open in 2000 for $150 million, grew as city planners worked with the world's best designers and architects to create a unique 21st century park, video-screen water sculptures, gardens and a $25 million stainless steel band shell by Frank Gehry covered by a latticework of steel tubes.
The centerpiece is a three-story, 110-ton polished steel sculpture called "Cloud Gate" that looks like a gleaming metal jellybean.
"Breathtaking," said Mayor Richard Daley, who will cut the ribbon before a performance by the Grant Park Orchestra Friday evening. No pop concerts will be held there until 2005.
Thousands of residents and tourists are expected to attend a $700,000 three-day party to celebrate the city's new front yard. Tours start every 30 minutes.
Private donors gave $205 million to the project, which sits atop an underground parking garage with room for 300 bicycles. There are lockers and showers. Ground was broken in August 1997.
Notable deaths of 2014 [PHOTOS]