The city is lit up in blue to mark the third anniversary of the attack.
The father of one of the fallen officers says he remembers the night of the attack.
"I can remember... I was sitting there watching TV when it happened. A news flash came - gunfire downtown. And I knew Patrick was downtown," the father said.
Sunday marked three years since Micah Johnson opened fire on a peaceful protest. The Army veteran killed four Dallas police officers and one transit officer. Authorities killed Johnson using a robot-delivered bomb. July 7, 2016, is considered the deadliest day for U.S. law enforcement since the Sept. 11, 2001, terror attacks.
A sculpture honoring Dallas officers Lorne Ahrens, Michael Krol, Michael Smith, and Patrick Zamarripa, and Dallas Area Rapid Transit Officer Brent Thompson will be unveiled Monday in front of police headquarters.
Downtown Dallas was again the site of a high-profile shooting last month, when a masked gunman attacked a federal courthouse. The gunman was the only fatality.
The Associated Press contributed to this story.