TOKYO - Japanese Emperor Akihito and Empress Michiko visited Tokyo Sky Tree, the world's tallest stand- alone communications tower, on Thursday ahead of its opening to the public, the Imperial Household Agency said.

Japanese Emperor Akihito (L) and Empress Michiko look out from the 450m (1,480 ft) high observatory at the Tokyo Sky Tree April 26, 2012. The world's tallest radio tower and the world's second tallest structure measures 634m (2080 ft) and will open to the public on May 22. [Photo/Agencies]

The imperial couple viewed the sight of Tokyo on the 450-meter second deck after hearing an explanation about the 634-meter tower, according to the agency.

The operator of Tokyo Sky Tree initially extended the invitation to the emperor in March, but the emperor's health condition at that time was not good after his heart surgery in February.

Tokyo Sky Tree complex, the capital's new tourist attraction, will officially open on May 22.