This is the bicycle rack recovered from the WTC on exhibit at the 9/11 Memorial Museum.

http://m.911memorial.org/blog/bicycle-rack-recovered-wtc-exhibit-91...

Source: 911memorial.org.

By Margaret Barng, 9/11 Memorial Deputy Communications Manager

"In the aftermath of 9/11, only one owner stepped forward to claim his bicycle, still locked to the rack after he spray painted the word 'save' in front of it. The status of the other owners and riders was unknown."

Attachment photo by Jin Lee - 9/11 Memorial Museum.