In Barcelona, Spain, baton-wielding police broke up demonstrations and sit-in protests by Catalan independence activists Monday, as an estimated 180,000 people marched on the first anniversary of a referendum on independence that was banned by Spanish authorities. Riot police clashed with demonstrators outside the headquarters of Spain’s national police; elsewhere, activists occupied roads, a highway and a high-speed rail line, stopping traffic for hours. A year ago, more than 800 people were injured after Spanish police stormed polling stations and tried to forcibly prevent people from voting in an independence referendum, firing tear gas and physically attacking prospective voters.