Biden visits church in Delaware to mark anniversary of death of his first wife and one-year-old daughter in car crash in 1972

President Joe Biden took a break from politics on Monday to mark the anniversary of the death of his first wife and daughter.

The president, along with first lady Jill Biden, attended mass at Joseph on the Brandywine in Wilmington, Del.

Biden's first wife Neilia Hunter Biden and their one-year old daughter Naomi were killed in car crash on this date in 1972. The two are buried in the cemetery at the church.

Neilia and Naomi were killed when their car was struck by a tractor-trailer as she took the kids to pick out a Christmas tree. Biden's sons Hunter and Beau also were  in the vehicle and seriously injured. They were a year and a day apart in age, at 3 and 4.

Hunter later died of brain cancer in 2015 at the age of 46. He is also buried at Joseph on the Brandywine.

The death of his first wife and young daughter haunted Biden's early political career. He had just been elected to the Senate - winning his first election in November 1972 - when the accident occurred.

Biden often tells the story of their passing - praising the first responders who helped aid his family - and admitting he thought about resigning from the Senate even before he took the oath of office.

On the advice of other senators he stayed in office. He was sworn into the Senate in the Wilmington hospital where Beau and Hunter Biden were being treated after the accident. 

As senator, Biden began a daily commute between Wilmington and Washington D.C. - it's about 90 minutes by train - so he could be with his young sons as they recovered. His sister Valerie and other family members helped out. 

Biden married Jill Jacobs in 1977 and they had a daughter, Ashley. 

He continued his commuting practice throughout his time as senator and vice president. As president he regularly spends weekends in Wilmington, where he and Jill have a home.

Biden left the White House on Sunday to be in his home state for the anniversary. He usually attends church on December 18 to mark Neilia's and Naomi's passing. Hunter Biden named his eldest daughter Naomi in honor of his late sister.

On Sunday night, the president and first lady were leaving dinner with their campaign staff when a car crashed into their motorcade in downtown Wilmington.

Biden appeared frozen in shock as a car rammed an SUV that was part of his motorcade before Secret Service agents rushed him into a vehicle and drove him from the area Sunday night.

A pool of reporters and photographers captured the dramatic footage that saw the president hurried into the back of his armored SUV by Secret Service agents, not knowing if the crash was part of a deliberate attack. 

The wreck occurred at the very moment Biden was walking out of a building. As the loud bang rang out, Biden muttered 'wow!' as he looked toward the sound, appearing surprised. 

The Secret Service appeared equally as stunned as the man they were protecting, seeming slow off the mark, taking almost ten seconds to bundle the nation's leader into the safety of his vehicle. 

The car involved in the crash was a silver copper Ford sedan with Delaware plates. It slammed into the side of a black U.S. Secret Service SUV that was shielding the motorcade.

The sedan tried to continue into the closed-off intersection before Secret Service personnel sprung into action and surrounded the vehicle with weapons drawn, instructing the driver to put his hands up.   

The name of the driver has not been released.