UNICEF caused a huge traffic jam last Sunday in New York City--but all for a good reason.

The charity drove 27 empty schoolbuses through the center of Manhattan during the UN General Assembly to highlight the 27 million children not in school in conflict zones.

The stunt, coordinated by creative agency KBS and media and production partner PCI, saw the buses travel from Brooklyn through lower Manhattan to Times Square emblazoned with banners with words such as "School zones shouldn't be war zones"; "Tonight's homework shouldn't include hiding," and "Avoiding landmines shouldn't be an extracurricular activity."

UNICEF also made a video from the event, featuring 19-year-old UNICEF Goodwill Ambassador Muzoon Almellehan, who was forced to give up her education when she fled Syria, and showing the empty buses, seatbelts left flapping, to a melancoly rendition of "The Wheels on the Bus."