King Charles III visited the 9/11 memorial in New York on April 29, 2026, with Bloomberg serving as his guide through the grounds rather than Mayor Mamdani. The visit came amid public tension between the monarch and the city's mayor over ideological differences regarding British imperialism and colonial history.

Mamdani, a socialist who has publicly criticized the monarchy's historical treatment of colonized peoples and the Irish, had signaled his limited participation in advance. In a Monday statement to reporters, he committed only to attending the wreath-laying ceremony to honor the more than 3,000 people killed in the September 11 attacks. "And that will be the extent of my meeting with the king and with others who are present," Mamdani said.

The mayor's public schedule showed he was committed to attending a Denim Day event at the Family Justice Center at 2 p.m., one hour after the wreath-laying ceremony began. The event raises awareness for victims of sexual assault.

Despite his previous criticisms of the British Crown, Mamdani greeted King Charles with a handshake and brief conversation during the memorial visit. The encounter came hours after Mamdani had publicly urged the king to return the Kohinoor diamond, a gem in the British crown jewels that was mined in and taken from India. "If I was to speak to the king separately from that, I would probably encourage him to return the Kohinoor diamond," said Mamdani, who is of Indian descent.

Bloomberg, who became New York City mayor in January 2002 after the 9/11 attacks, led the royal couple on their tour of the memorial grounds. The former mayor was not in office during the terrorist attacks, which occurred under then-Mayor Rudy Giuliani's leadership.