This is a file from the Wikimedia Commons and may be used by other projects. Information from its description page there is shown below. Commons is a freely licensed media file repository.
Summary
DescriptionO'Hare Chicago CTA station-2.jpg
As seen from above the stairs Canon 5D MKII + 50/1.2L
This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: slightly rotated, strategically cropped, and removal of the tip top of some guy's hair. The original can be viewed here: O'Hare Chicago CTA station.jpg: . Modifications made by Peterfitzgerald.
Licensing
I, the copyright holder of this work, hereby publish it under the following license:
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.