DENVER (AP) -- Denver International Airport's often-maligned sculpture of a rearing blue mustang with glowing red eyes is about to turn 5 -- an important milestone for public art in the city.

Why? Because petitions to remove artwork aren't accepted in the first five years.

Now that the 32-foot-tall horse -- nicknamed "Bluecifer" by snickering locals -- is about to celebrate its birthday, a debate about what to do with the sculpture is sure to begin.

KUSA-TV reports (http://on9news.tv/VytuWz) to make a pitch to remove or relocate the sculpture, a petition must be filed with the Denver Commission on Cultural Affairs.

The sculpture was created by Luis Jimenez, who was killed in 2006 when a section of the unfinished work fell on him at his studio. Jimenez's sons completed the sculpture, which was installed Feb. 11, 2008.