The Millennium Celebration was an Epcot focused celebration of the coming of the year 2000 to mark the Dawn of the 21st Century that ran from October 1, 1999 to January 1, 2001.
The theme song for the event was Celebrate the Future Hand in Hand.
Additions for the year included:
Tapestry of Nations, a parade with massive puppets and drum floats
IllumiNations: Reflections of Earth
Millennium Village, a pavilion hosting multiple nations not covered in the rest of World Showcase
Journey Into Your Imagination, the much criticized overhaul of the Imagination pavilion.
The "Wand" icon placed onto Spaceship Earth
An updated version of Innoventions
Leave a Legacy, a series of monolith structures at the entrance of Epcot where guests could purchase photo squares to be added to the sculptures and leave a mark on the park, similar to the Walk Around the World bricks.