The first tribute held Tuesday began with a wreath-laying ceremony dedicated to the three people who died, more than 260 people who were injured and the first responders, doctors and nurses who helped them.
Families of the bombing victims - Martin Richard, Krystle Campbell and Lu Lingzi - and of Massachusetts Institute of Technology police Officer Sean Collier, who was killed in the aftermath of the blasts, attended the ceremony.
"These terrorist acts that keep happening, we need to rise above them and prove that we're resilient and we're strong and that we can create something good out of something so awful," said Sally Duval, a Boston Marathon runner.
Boston police investigate 2 backpacks, clear area
A man was charged tonight with possession of a hoax device, disorderly conduct and disturbing the peace after two suspicious bags were found near the finish line of the Boston Marathon amid stepped-up security on the anniversary of the bombings that shook the city a year ago today.
The device the suspect had was a rice cooker, not an actual explosive device, police said.
The two suspicious bags -- only one of which police say they believe the man dropped -- were both exploded this evening after the suspect had been detained for questioning.
Police said the bags were left in the area of Boylston St. and Exeter St., and the road was closed.
Officials honor victims, bombing survivors speak
Vice President Joe Biden, Gov. Deval Patrick and former Mayor Tom Menino were among the dignitaries that arrived earlier Tuesday to honor the victims during a program at the Hynes Convention Center. Survivors of the bombing also spoke.
"This day will always be hard, but this place will always be strong," said Menino.
Biden said the courage shown by survivors and those who lost loved ones is an inspiration for other Americans dealing with loss and tragedy.
"You have become the face of America's resolve," he said.
Biden also praised the 36,000 runners who plan to run the marathon next Monday, saying they will send a message to terrorists.
"America will never, ever, ever stand down," he said, to loud applause. He added, "We own the finish line."
At about 2:45 p.m., a moment of silence was held at the marathon finish line marking the time and place the two bombs exploded. Church bells then rang and a flag was raised.
People around the country also paid their respects. A group of runners raced in a month-long relay from Los Angeles to Boston to raise money for the wounded. The runners traveled 10-to-20 miles, then passed the baton to runners in another city.
In Washington, President Barack Obama also observed the anniversary with a moment of silence.
"Today, we recognize the incredible courage and leadership of so many Bostonians in the wake of unspeakable tragedy," Obama said in a statement.
"And we offer our deepest gratitude to the courageous firefighters, police officers, medical professionals, runners and spectators who, in an instant, displayed the spirit Boston was built on - perseverance, freedom and love."
Secretary of State John Kerry tweeted the following message: "One year later, even if you were miles from home, no Bostonian will forget this day. Remember victims, honor heroes. We are #BostonStrong.
Boston bombing suspects planned NYC attack, police say
Authorities allege brothers Tamerlan Tsarnaev, 26, and Dzhokhar Tsarnaev, who was 19 at the time of the bombings, were responsible for the attack. Tamerlan died in a shootout with police four days after the attack, while the latter was captured and is being detained pending trial.
Dzhokhar has pleaded not guilty to 30 federal charges, including using a weapon of mass destruction. He faces a possible death sentence. His trial is set to begin in November.
2014 Boston Marathon to be held Monday
The 118th Boston Marathon is scheduled for next Monday, and is expected to be the second-largest in history.
Obama said this year's race will "show the world the meaning of Boston Strong as a city chooses to run again."
ABC News and The Associated Press contributed to this report.