A woman wipes away tears Monday as she holds up a picture of a loved one during a ceremony at ground zero in New York.

NEW YORK — Americans commemorated 9-11 on Monday with tear-streaked tributes, a presidential warning to terrorists and appeals from victims' relatives for unity and hope 16 years after the deadliest terrorist attack on U.S. soil.

Looking out at the solemn crowd at ground zero, Debra Epps said she views every day as time to do something to ensure that her brother, Christopher Epps, and thousands of others didn't die in vain.

“What I can say today is that I don't live my life in complacency,” she said. “I stand in solidarity that this world will make a change for the better.”

Thousands of family members, survivors, rescuers and others gathered for the hourslong reading of victims' names at the World Trade Center, while President Donald Trump spoke at the Pentagon and Vice President Mike Pence addressed an observance at the Flight 93 National Memorial near Shanksville, Pennsylvania.

The Capitol was a possible target of the terrorist piloting Flight 93. Instead, it crashed near Shanksville after the passengers took action. Thirty-three passengers and seven crew members were killed.

The ceremony on the National Sept. 11 Memorial plaza in New York strives to be apolitical, allowing politicians to attend but not to speak. Yet last year's 15th anniversary ceremony became entangled in the presidential campaign when Democratic nominee Hillary Clinton left abruptly, stumbled into a van and ultimately revealed she'd been diagnosed days earlier with pneumonia.

This year, the focus remained on the names read out beneath the waterfall pools and lines of trees.

While many Americans may no longer interrupt their days to observe the 9-11 anniversary, the ceremony remains a touchstone for many victims' families and friends.“I'll come every year for the rest of my life,” said Rob Fazio, who lost his father, Ronald Fazio. “It's where I get my strength.”After 15 years of anniversaries, the reading of names, moments of silence and tolling bells have become rituals, but each ceremony takes on personal touches. Name-readers Monday gave updates on family graduations and marriages and remembered loved ones' flair for surfing or drawing on coffee-shop napkins.A few never even got to know the relatives they lost on Sept. 11, 2001.“I wish more than anything that I could have met you,” Ruth Daly said after reading names in remembrance of her slain grandmother, Ruth Lapin. “I'm very proud to be your namesake. I hope you're watching down on me from heaven.”

A man stands at the edge of a waterfall pool Monday during a ceremony at ground zero in New York Holding photos and reading names of loved ones lost 16 years ago, 9-11 victims' relatives marked the anniversary of the attacks with a solemn and personal ceremony.