U.S. Transportation Secretary Ray LaHood came to Philadelphia Monday to celebrate the start of renovations at Dilworth Plaza. The plaza is known to many as the site of the Occupy Philadelphia protest.

Construction of a new park and transportation improvements outside City Hall will cost $50 million.

On Monday, a "groundbreaking" took place on the ninth-floor of an office building overlooking the plaza.

The word used most often by a series of prominent speakers was "vision," in particular the vision of Paul Levy, head of the Center City District. He is credited with sticking with an expensive project that was not an obvious candidate for financing during a major recession.

"Our goal here is to create a first-class park, a great public space and a signature gateway to public transit at Dilworth Plaza," Levy said Monday. He sees the plaza as bridging the city's main attractions -- from the art museum to the office buildings.

The federal government is picking up about a third of the tab; LaHood was on hand to make the case that investment in infrastructure projects such as this one will put Americans to work.

"I do a lot of traveling, and I've been to a lot of cities in America. No city has such extraordinary leadership," LaHood said during the ceremony. "You are all very blessed here."

The plaza plans include a cafe, a skating rink and elevators to below-ground public transit. The revamped Dilworth Plaza is slated to open in 2014.