Iranian boys take a selfie as they stand beside the light installation on Azadi tower in Tehran, Iran, on Oct. 5, 2015. The German artist Philipp Geist develops light installation made of colored words and concepts in different languages titled "Gate of Words" at the Azadi tower, a symbol of Tehran, over the past three nights to visualize the topics of freedom, peace, space, and time artistically. (Xinhua/Ahmad Halabisaz)

Iranian women pose for photo as they stand beside the light installation on Azadi tower in Tehran, Iran, on Oct. 5, 2015. The German artist Philipp Geist develops light installation made of colored words and concepts in different languages titled "Gate of Words" at the Azadi tower, a symbol of Tehran, over the past three nights to visualize the topics of freedom, peace, space, and time artistically. (Xinhua/Ahmad Halabisaz)

People watch the light installation on Azadi tower in Tehran, Iran, on Oct. 5, 2015. The German artist Philipp Geist develops light installation made of colored words and concepts in different languages titled "Gate of Words" at the Azadi tower, a symbol of Tehran, over the past three nights to visualize the topics of freedom, peace, space, and time artistically. (Xinhua/Ahmad Halabisaz)