Hundreds of thousands of people gathered for gay pride parades, parties and celebrations around the world Sunday. Most events were peaceful, but in Istanbul, Turkish police fired water cannon and rubber pellets to disperse a crowd. It was not immediately clear why Turkish police stopped marchers in Istanbul, where gay pride parades have been held in previous years. Turkish media reported that police said people would not to be allowed to march this year. In New York, massive crowds gathered ahead of the city’s annual gay pride parade, which was first held in 1970. Organizers said they expected a record...