Photo taken on Feb. 7, 2013 shows the clock's hour bell nicknamed 'Big Ben' in London, Britain. The "Big Ben" bell turns 160 years since it began striking the hour on July 11, 1859. Photo:Xinhua

Photo taken on Feb. 7, 2013 shows the clock's hour bell nicknamed 'Big Ben' in London, Britain. The "Big Ben" bell turns 160 years since it began striking the hour on July 11, 1859. Photo:Xinhua

Photo taken on March 14, 2018 shows decorative roof parts being inspected in London, Britain. The "Big Ben" bell turns 160 years since it began striking the hour on July 11, 1859. Photo:Xinhua

Photo taken on April 21, 2016 shows detail of the Great Clock mechanism in the Elizabeth Tower in London, Britain. The "Big Ben" bell turns 160 years since it began striking the hour on July 11, 1859. Photo:Xinhua

Photo taken on March 20, 2019 shows the east (L) and north (R) dials of the Big Ben in London, Britain. The "Big Ben" bell turns 160 years since it began striking the hour on July 11, 1859. Photo:Xinhua

Photo taken on May 21, 2019 shows the finished north dial of the Big Ben in London, Britain. The "Big Ben" bell turns 160 years since it began striking the hour on July 11, 1859. Photo:Xinhua

Photo taken on May 21, 2019 shows gilding of cast iron roof elements of the Big Ben in London, Britain. The "Big Ben" bell turns 160 years since it began striking the hour on July 11, 1859. Photo:Xinhua