Troops were also deployed to key locations, such as Buckingham Palace, the prime minister's residence at 10 Downing Street and Parliament.
Olivia Campbell joins eight-year-old Saffie Roussos and Georgina Callander,18, among the first victims of the attack be identified.
Split-second decisions during the terrifying moments after a suicide bomber targeted Ariana Grande fans transformed many regular people into heroes.
The president and the pontiff have disagreed in the past on numerous issues.
A court ruled that the Taiwan's current code was a violation of two articles of the constitution of the Republic of China.