A pedestrian walks past the mural "28 Blocks" by artist Garin Baker. (Ricky Carioti/The Washington Post)

It might have been the simple gray tones of the hulking monument under construction. Or maybe it was the contours of muscular men hard at work on what would become one of the most venerated statues in the nation. Or possibly it was the words beneath it:

"Without culture there can be no growth. . . . Without action, no progress. And without conflict, no victory." — Frederick Douglass.

Whatever it was, joggers stopped, cyclists dismounted and Metro riders peered out their windows during evening commuting hours this week to glimpse the newly installed mural that pays homage to the workers who built the statue in the Lincoln Memorial.

"It's beautiful," said Prameeka Patura, 27, who passed by the mural on an evening walk. "It's very creative. Now I'm thinking I need to go back and look up all this history."

"28 Blocks" by New York artist Garin Baker sits along the Metropolitan Branch Trail — a popular pedestrian and cyclist commuter trail in Northeast Washington that is surrounded by train tracks to the east and industrial buildings on the west. It is a tribute to the men — many of whom were the first and second generation of black men born free — who built the 120-ton marble statue. Italian immigrants also helped build the statue, which was designed by sculptor Daniel Chester French to sit in the memorial, planned by architect Henry Bacon.

The name comes from the 28 blocks of marble used to erect the statue between 1914 and 1922. The marble was carved from mountains in northwestern Georgia by the sons of African slaves, according to the D.C. Department of General Services. The marble was then sent to New York, where the statue was carved block by block. The blocks were later transported from New York to Washington through Union Station, upon which they were assembled for the first time.

The Department of General Services put out a $50,000 national call in spring 2016 for artists to submit proposals for a mural that would cover the vacant Penn Center building the city owns where New York Avenue NE meets the trail.

The city received 20 applications and ultimately settled on Baker's vision because the mural itself was striking and its message was particularly salient for that space, according to Joia Nuri, a public information officer for the department.

The Metropolitan Branch Trail runs parallel to the train tracks that ferry people from New York to Union Station. Visitors arriving from New York to the nation's capital by rail will be able to see the mural out their windows just before reaching the station.

"We selected this mural because of its connection to Washington. The Lincoln Memorial is one of the most iconic monuments in Washington," Nuri said. "The reaction has been phenomenal. We have just been standing there and watching people go by and stop and take pictures."

Baker said he was researching the history of the Lincoln Memorial and was "blown away" by the story. From there, he wanted to find a way to transform that history into a mural.

"When I started doing research, the story really started to unfold. I found a really symbolic story about America," Baker said. "These workers' souls and their hearts and their dreams are imbued in those stones. For an artist, it's a good thing."

It took Baker four months to hand-paint the mural on 156 sections of parachute cloth in his New York studio. He then used a special polymer glue to attach the mural to the facade of the building.

He said the color scheme of black, white and gray is intentional and carries symbolism.

"People see things in black and white, but it's really not the full story," he said. "Only through all the shades of gray do we see the full truth."

Nuri said the city has no immediate plans to put the Penn Center building to use, but it might eventually be used by D.C. Public Schools.