BERLIN (AP).- Germany’s parliament says restrictions on visits to the cupola of its Reichstag building — long a Berlin tourist magnet — will be relaxed later this month, but sightseers will have to register in advance. The Reichstag’s glass cupola, British architect Norman Foster’s popular 1990s addition to the historic building, was closed to visitors last November after the Interior Ministry warned of an increased terrorism threat in Germany and raised security levels. It was subsequently reopened only to people on full tours of the parliament building or with reservations at its rooftop restaurant. Parliament’s lower house said Wednesday that, starting April 21, visitors who only want to visit the cupola will be admitted again. They will have to register at least two working days in advance.