On Monday, as workers returned for their first official day back in the former Building 197 at the Naval Sea Systems Command headquarters at the Washington Navy Yard, a waterfall trickled over a black granite remembrance wall, where a lighted panel read:

“We memorialize as heroes those we lost and pledge that their lives and deeds shine forever bright. It was a day when ordinary people became extraordinary heroes and showed that courage lies in us all, even in the face of tragedy. Thousands returned to work just days later as a family. They would not let fear keep them away. They had a fleet to put to sea. — Secretary of the Navy Ray Mabus.”

Inside the entry area, there is a space dedicated to the 12 people who died when contractor Aaron Alexis went on a shooting rampage at the building on Sept. 16, 2013: Richard “Mike” Ridgell, Michael Arnold, Martin Bodrog, Arthur Daniels Sr., Sylvia Frasier, Kathleen Nark Gaarde, John Roger Johnson, Mary Frances DeLorenzo Knight, Frank Kohler, Vishnu Pandit, Kenneth Bernard Proctor Sr. and Gerald Read.

Employees quietly took seats on marble benches in front of the 12 lighted boxes that commemorate the victims.

The memorial was unveiled Sunday during a private ceremony with the victims’ families. Lying on the gray pebbles at the base of the wall was a bouquet of sunflowers. Between the back benches, a comfort dog — a golden retriever — playfully sniffed the hand of a mourner.

On Monday morning during the reopening ceremony, Rear Adm. Katherine Gregory welcomed workers.

“Yesterday, we met with the family of the victims of the horrible incident,” Gregory told the crowd gathered outside. “We paid tribute to their lost and we resolved …. that we remembered, as we moved forward, everything that had been lost and to make it stronger and better. Today, we make good on that resolution. Today, you make good on that resolution as you step into this building and step into your future.”

Next to the podium was Vice Adm. William Hilarides, who leads NAVSEA. Hilarides explained that it is part of a Navy tradition that when a new ship is launched, “when it touches water for the first time, it is named and blessed at a christening ceremony. When the ship is fully functional, there will be a second ceremony called a commissioning that is the turnover of the ship fully ready to do its mission for the fleet.”

Monday’s ceremony was for the christening of the building. “As head of our Navy shipbuilding, it is only fitting, we bless our headquarters in this tradition,” Hilarides said.

The vice admiral’s wife, Beverly Hilarides, then stepped to the podium and announced: “I christen thee Humphreys. God bless all who will work here.” She walked to the building and smashed a bottle of champagne against the red brick. The crowd cheered.

The building has been renamed in honor of Joshua Humphreys, a shipbuilder who designed the first Navy frigates — USS United States, USS Constitution, USS Congress, USS President, USS Constellation and USS Chesapeake. The five floors in the building have been named after each frigate Humphreys designed.

Hilarides said a new name for the building was an important reminder of NAVSEA’s resilience.

A commissioning ceremony for the building is scheduled for April, after workers have completed their move into the building.