A woman smokes marijuana during the annual 4/20 marijuana rally on Parliament Hill in Ottawa, Ontario, Canada, April 20, 2017. (Photo by Chris Wattie/Reuters)

Francis Sierra, 23, smokes as she competes for the longest ash during the XVIII Habanos Festival in Havana, March 3, 2016. (Photo by Alexandre Meneghini/Reuters)

A general view shows smoke and volcanic ashes billowing from volcano Cotopaxi in Pedregal, Ecuador, late 07 October 2015. (Photo by Jose Jacome/EPA)

An injured fan is helped by a riot policeman during clashes between Red Star Belgrade and Partizan Belgrade fans in the stadium before the teams' Serbian Superliga soccer match in Belgrade, April 25, 2015. Serbian league leaders Partizan Belgrade held champions and bitter city foes Red Star to a 0-0 draw in a derby match marred by bad crowd trouble before kickoff on Saturday. The start was delayed for 45 minutes after home Red Star supporters pelted riot police with seats and flares, forcing officers to retreat from the north tier that houses the club's diehard fans. (Photo by Marko Djurica/Reuters)

For our latest mission, we put a Carnegie Hall orchestra in the middle of New York City and placed an empty podium in front of the musicians with a sign that read, “Conduct Us.” Random New Yorkers who accepted the challenge were given the opportunity to conduct this world-class orchestra. The orchestra responded to the conductors, altering their tempo and performance accordingly. This project was a collaboration with Carnegie Hall and Ensemble ACJW.

A man smokes marijuana during a demonstration in support of the legalization of marijuana in Medellin, May 2, 2015. (Photo by Fredy Builes/Reuters)

A Muslim man carries holy incensed smoke through a pedestrian subway in Mumbai, India, May 13, 2016. (Photo by Danish Siddiqui/Reuters)

A reveller is seen smoking at the annual gay pride parade in Santo Domingo in the Dominican Republic July 03, 2016. (Photo by Ricardo Rojas/Reuters)