Ulrich Blanché, an art history lecturer at Heidelberg University in Germany, called the piece a “very well executed” stencil ... that was part of Banksy’s “Girl With Balloon” series ...

Almost as soon as Banksy revealed the piece back in 2013, an anonymous tagger brazenly walked up and spray-painted the words "Omar NYC" in red beside the balloon, to the dismay of onlookers. Days ...