Lights will flick off throughout the Twin Cities on Saturday night as civic leaders join a global movement to conserve energy. During Earth Hour, iconic monuments such as Paris’ Eiffel Tower, London’s House of Parliament and New York’s Empire State Building will go dark when the clock strikes 8:30 p.m. local times. Minnesota’s State Capitol, along with dozens of other businesses and local institutions plan, to participate by shutting off all nonessential lighting for that hour. For the event, billed as “the world’s largest voluntary action for the environment,” the cities of Minneapolis, St. Paul and Eden Prairie are encouraging...