A Police officer checks a man wearing a carnival costume in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. Police are also examining backpacks and bags and using metal-detecting wands before revelers are allowed into St. Mark's Square, the heart of the Venetian carnival. (Photo by Luigi Costantini/AP Photo)





A mask salutes in St. Mark's Square on the occasion of the Venice Carnival, in Venice, Italy, Saturday, January 30, 2016. People attended the Venice Carnival, celebrated Saturday under heightened security following the sexual assaults on New Year's Eve in Cologne and the ongoing terror threat in Europe. Authorities have increased surveillance throughout the city, including the number of officers on patrol, both under-cover and in uniform. (Photo by Luigi Costantini/AP Photo)





A mask crosses St. Mark's Square as police officers patrol on the occasion of the Venice Carnival, in Venice, Italy, Saturday, January 30, 2016. (Photo by Luigi Costantini/AP Photo)





A masked woman goes through a security check in Venice, Italy, Sunday, January 30, 2016. (Photo by Luigi Costantini/AP Photo)





Artists blow bubbles in St. Mark's Square in Venice, Italy, Sunday, January 31, 2016. (Photo by Luigi Costantini/AP Photo)





Police officers check a man wearing a carnival costume in Venice, Italy, Sunday, January 31 2016. (Photo by Luigi Costantini/AP Photo)





Irene Rizzi, center, poses with a man impersonating the Doge of Venice, right, after descending from the bell tower into St. Mark's Square, in Venice, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. Sunday's main crowd-pleaser known as the Flight of the Angel went off without a hitch. In that event, a costumed young woman, attached by wires, “flies” over the crowd, starting from St. Mark's bell tower and gradually descending to the square. (Photo by Luigi Costantini/AP Photo)





Italian policemen check masked revellers as they arrive at San Marco Piazza during the Venice Carnival, January 31, 2016. (Photo by Alessandro Bianchi/Reuters)





A masked reveller poses at San Marco Piazza during the Venice Carnival, January 31, 2016. (Photo by Alessandro Bianchi/Reuters)





Revellers watch as the traditional Columbine descends from Saint Mark's tower bell on an iron cable during the Venice Carnival, January 31, 2016. (Photo by Alessandro Bianchi/Reuters)





A masked reveller takes a picture as the traditional Columbine descends from Saint Mark's tower bell on an iron cable during the Venice Carnival, January 31, 2016. (Photo by Alessandro Bianchi/Reuters)





A reveller (C) watches as the traditional Columbine descends from Saint Mark's tower bell on an iron cable during the Venice Carnival, January 31, 2016. (Photo by Alessandro Bianchi/Reuters)





A masked reveller (R) walks before a check by Italian policemen in San Marco Piazza during the Venice Carnival, January 31, 2016. (Photo by Alessandro Bianchi/Reuters)





Revellers are seen in the Caffe Florian coffee shop in Saint Mark's Square during the Venice Carnival, Italy January 31, 2016. (Photo by Manuel Silvestri/Reuters)





Revellers are seen in the Caffe Florian coffee shop in Saint Mark's Square during the Venice Carnival, Italy January 31, 2016. (Photo by Manuel Silvestri/Reuters)





Revellers are seen in the Caffe Florian coffee shop in Saint Mark's Square during the Venice Carnival, Italy January 31, 2016. (Photo by Manuel Silvestri/Reuters)





Revellers sit at the Caffe Florian coffee shop in Saint Mark's Square during the Venice Carnival, Italy January 31, 2016. (Photo by Manuel Silvestri/Reuters)





The “parade of the Maries” crosses St. Mark's Square on the occasion of the Venice Carnival, in Venice, Italy, Saturday, January 30, 2016. People attended the Venice Carnival, celebrated Saturday under heightened security following the sexual assaults on New Year's Eve in Cologne and the ongoing terror threat in Europe. Authorities have increased surveillance throughout the city, including the number of officers on patrol, both under-cover and in uniform. (Photo by Andrea Merola/ANSA via AP Photo)





People wearing costumes gather in St. Mark's Square in Venice, Italy, Sunday, January 31, 2016. (Photo by Luigi Costantini/AP Photo)





Irene Rizzi blows a kiss after descending from the bell tower into St. Mark's Square, in Venice, Sunday, January 31, 2016. (Photo by Luigi Costantini/AP Photo)