The Philadelphia City Archives – the contents of about 15,000 boxes of documents, photos, and film – has moved from its previous home in the basement of the old Bulletin building in West Philly to a $10 million, state-of-the-art facility in Northern Liberties.

City officials opened the new archives, 548 Spring Garden St., on Thursday afternoon.

The collection of city records ­– said to be one of the most comprehensive in the country -- includes the William Penn City Charter from 1701, documents from the 18th century with the signatures of Alexander Hamilton and Benjamin Franklin, the death certificate of Civil War-era scholar and activist Octavius V. Catto, the blueprints to City Hall, and even a photograph of Philadelphia’s first police car.

Before moving to the new 65,000-square-foot facility, the trove had been stored in the football-field-size basement at 3101 Market St. for 20 years.

“When I first became commissioner, I told my team that we should go look at the records in the basement on Market,” Records Commissioner James Leonard said during a news conference on Thursday.

“When we got there, they said, ‘Commissioner, this is what we have to move.’ And then there was a loud thud, which was the sound of me fainting.”

Over the last few years, Leonard and his team have painstakingly moved the archives, including 2 million photographs and 400 film items, into its new climate-controlled home. (The Department of Records is in the process of digitizing its glass negatives, which date from the 1880s.)

Beyond its value to historians, the city archive is a resource for people looking into their family history and for professional genealogists. The collection contains birth and death certifications, marriage certificates, naturalizations, prison records, court records, and property deeds.

“It’s a phenomenal institution that has been little understood,” said Vistula Chapman-Smith, a former Philadelphia records commissioner. “It’s not a fragmented collection. It tells stories from beginning to end.”

The public can visit Monday through Friday from 9 a.m. to 4:30 p.m.

“It’s important for people to know what is held in this treasure trove because it allows us to understand Philadelphia’s unique position in the story of our nation,” Chapman-Smith said.

The new facility includes a new permanent public artwork, Charting a Path to Resistance, created by Chestnut Hill artist Talia Greene.

Greene said the mural was inspired by the history of abolitionism in Philadelphia. When she visited the archives for the first time, she walked by a redlining map – said to be one of the few in possession of any city -- and wound up incorporating it into the artwork.

The redlining map, drawn up by a private company and acquired by city officials in 1944, was used by banks and loan companies for housing discrimination against African Americans. (It is not clear why the city was in possession of the map, but officials said that there was some degree of involvement between the city and the people who made redlining maps.)

“I wanted to provide a window into the larger history of Philly,” Greene said. “Maps layer time with geography, so they always tell really interesting stories.”

Visitors to the building can download a free app that includes animations, text, and voiceovers to explore the artwork in greater depth.