Here is a list of some of the worst bombings in the U.S. dating to the 1800s, including some famous attempts that failed:
— April 15, 2013: Two bombs explode in the packed streets near the finish line of the Boston Marathon, killing three people and injuring at least 130.
— Jan. 17, 2011: A backpack bomb is placed along a Martin Luther King Day parade route in Spokane, Wash., meant to kill and injure participants in a civil rights march, but is found and disabled before it can explode. White supremacist Kevin Harpham is convicted and sentenced to 32 years in federal prison.
— May 1, 2010: Pakistani immigrant Faisal Shahzad leaves an explosives-laden SUV in New York's Times Square, hoping to detonate it on a busy night. Street vendors spot smoke coming from the vehicle and the bomb is disabled. Shahzad is arrested as he tries to leave the country and is sentenced to life in prison.
— Dec. 25, 2009: The so-called "underwear bomber," Nigerian Umar Farouk Abdulmutallab, is subdued by passengers and crew after trying to blow up an airliner heading from Paris to Detroit using explosives hidden in his undergarments. He's sentenced to life in prison.
— Sept. 11, 2001: Four commercial jets are hijacked by 19 al-Qaida militants and used as suicide bombs, bringing down the two towers of New York City's World Trade Center and crashing into the Pentagon. Nearly 3,000 people are killed in New York, Washington and Pennsylvania.
— Jan 22, 1998: Theodore Kaczynski pleads guilty in Sacramento, Calif., to being the Unabomber in return for a sentence of life in prison without parole. He's locked up in the federal Supermax prison in Colorado for killing three people and injuring 23 during a nationwide bombing spree between 1978 and 1995.
— Jan. 20, 1998: A bombing at an abortion clinic in Birmingham, Ala., kills one guard and injures a nurse. Eric Robert Rudolph is suspected in the case.