A police officer gets brutally executed in the Bronx as she sits in her squad car. A train carrying 150 people derails in Manhattan's Penn Station. And those crazy costumed characters in Times Square are still running wild.

But where's the city's mayor? Not there. He flew to Hamburg, Germany, to "join leftist protesters at the G-20 summit in Germany," the New York Post reports.

Mayor Bill de Blasio on Thursday skipped an NYPD swearing-in ceremony made somber by this week’s assassination of a cop — then hours later revealed he was busy preparing to jet off on a surprise trip to join leftist protesters at the G-20 summit in Germany.

Hizzoner’s overseas jaunt was kept under wraps until just 90 minutes before he took off from Newark Airport. A last-minute announcement said he “will attend several events surrounding the G-20 Summit, including Saturday’s Hamburg Zeigt Haltung rally.”

De Blasio will be the keynote speaker, organizers of the demonstration — Hamburg Shows Attitude — tweeted.

The mayor also made sure the free trip will include a visit with his son, Dante, a Yale University student who’s spending the summer on an internship in Berlin, a City Hall spokesman said.

The head of the New York Police Department Sergeants Union was not at all happy.

“As the city mourns, its leader flees,” Ed Mullins said. “And then he wonders why he has a problem with the police. A real leader stays with the city in this time of hardship.”

De Blasio's trip — and his decision to skip the swearing-in ceremony — was crudely announced on Twitter. "The Mayor will depart this evening for Berlin & Hamburg, Germany. He will attend several events surrounding the G20. +details to follow," the mayor's spokesman Eric Phillips tweeted.

De Blasio is now joining leftist anarchists who are setting cars on fire and marauding through the streets of Hamburg, clashing violently with police clad in riot gear who are using water cannons, pepper spray and batons to disperse protesters. The protest is titled "G20: Welcome to Hell," and includes throngs of anti-capitalist protesters intent on disrupting the annual meeting of 20 major world economies.

Assemblywoman Nicole Malliotakis, a Republican planning to run against de Blasio in the upcoming mayoral race, mocked the mayor's sudden disappearance.

Donald Trump Jr. also bashed the mayor.

The mayor's office says de Blasio should be back in time for the funeral of NYPD Officer Miosotis Familia — assuming he's not having so much fun protesting capitalism that he doesn't just stay the weekend.