World Trade Cener North Tower Reflecting Pool. Photo: Wikimedia Public Domain

Wikimedia Public Domain
This file is licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license.
You are free:
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.
https://commons.wikimedia.org/wiki/File:North_Tower_Fountain_National_September_11_Memorial_%26_Museum_(Sept._17,_2011).jpg