The Empire State Building went dark Tuesday evening to honor the victims of Monday's explosion in Manchester, England.
The Yankees also played God Save the Queen before their game at the Stadium to show their solidarity with Manchester.
British Prime Minister Theresa May says the terror threat level has been raised, because intelligence officials believe another attack may be imminent.
May says the Manchester Arena attacker. identified as 22-year-old Salman Abedi, may have been part of a larger network.
He and at least 22 others were killed, and dozens more were wounded, after he set off an explosive device outside the arena just as people were leaving the Ariana Grande concert.
Thousands turned out Tuesday for a vigil in front of Manchester City Hall.
Andy Burnham, the mayor of Manchester, says the terrorists will never divide his city.
"The answer isn't to ramp up the rhetoric, as we hear sometimes from politicians around the world. In the end, this is the answer for people to come together and say, 'This is us, these are our values,'" Burnham said.
The pop group "Take That" has postponed three planned shows scheduled at the arena later this week.
Ariana Grande has also suspended her tour.