Long lines, beefed up security at 9/11 Museum in New York

Security is always in force at the museum and surrounding memorial plaza, but was especially formidable on Saturday. An armored personnel carrier was parked just outside the entrance to the museum, and police officers carrying heavy arms maintained a very visible presence.

An employee at the memorial, who did not give her name because she isn't authorized to talk to the media, said security is always tight but the officers' weaponry and K-9 patrols were a step up.

Roberta Dozier, visiting from Southport, N.C., was glad to see it: "We have noticed advanced security, which is a good feeling."

French President Francois Hollande has vowed that France will wage "merciless" war on the Islamic State group, after the jihadists claimed responsibility for the attacks. Terrorists launched gun attacks at Paris cafes, detonated suicide bombs near France's national stadium and killed hostages inside a concert hall during a rock show.

Shannon Reynolds of Franklin, Mass., started learning of the attacks via Facebook posts on Friday, the night before she and her foster daughter Desirae White took a trip to New York to visit sites including the 9/11 museum. She was a bit startled at the sight of heavily armed officers patrolling throughout the memorial plaza, but relieved all the same.

“Why do they have to have guns?” Desirae asked as several officers walked by.

“For protection,” Reynolds said.

Desirae is 7, too young to have known the post-Sept. 11 panic that gripped this country. Reynolds was wistful at the thought of her growing up in an era where terrorist strikes seem to have become all too common.

“It’s still happening on such a scale, another orchestrated hit,” she said. “One of these days, hopefully, we’ll have peace.”

Contributing: The Associated Press