After years of plans, the National Museum of African American History and Culture opened on Sept. 24 near the Washington Monument. The structure celebrates freedom and protects some 33,000 unique artifacts, including an 80-ton railcar.

Smithsonian general contractors Clark/Smoot/Russell in 2012 broke ground on the five-story, 409,000-sq-ft structure, 60% of which is underground and built to withstand the area’s high water table. The $365-million job, which grew in cost to $540 million including construction and installation, was designed by architects Freelon/Adjaye/Davis Brody Bond/SmithGroupJJR.

The project overcame tragedy: Last year, Ivan Smyntyna, a 35-year-old worker of subcontractor MillerClapperton, died in a scaffolding accident that brought a $6,000 OSHA fine. The employer notes on its Facebook page that it helped to gather more than $14,800 in donations for the family.

As for the finished museum, Deryl McKissack, CEO of McKissack & McKissack, whose ancestors learned the construction trade as slaves, calls it “the culmination of a lot of hard work and realization of many dreams.” McKissack provided the owner with program, design and construction management for “an enormous project with lots of moving parts involving over 100 subcontractors.”