The leaders of Eli Broad's planned Grand Avenue museum of contemporary art, to be called simply the Broad, will make news in three separate ways on Monday.

They will unveil designs for a new plaza adjacent to the museum by architects Diller, Scofidio + Renfro and landscape architect Walter Hood. They will name Bill Chait, who runs Bestia in the arts district, to oversee a new restaurant on the plaza with Timothy Hollingsworth, former chef de cuisine at French Laundry in the Napa Valley.

And they will announce that the opening of the museum has been pushed back from this fall to an unspecified date next year.

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It doesn't require too much cynicism to conclude that the release of the first two items is meant, in part, to draw some attention from the third. But for me the design of the plaza is the most meaningful bit of news here.

And that's not just because Bunker Hill is short on public space that is well-designed and friendly to pedestrians. It's also because the details of how the plaza will operate — and who will own it — make up a multilayered and in the end rather opaque story.

If the last few years have taught us anything about the role that public squares play in the contemporary city, it is that they are both more valuable to civic life and more fraught with legal and political complexity than ever.

The rise of digital technology has not dimmed our desire to gather in public. In fact, it may have intensified it. Recent revolutions have been sparked by a combination of text message and sit-in.

But scratch the legal surface of any public square, particularly in this country, and you're likely to find a tangle of restrictions and, in many cases, concessions to private interests.

In 2011 the Occupy movement sprung from Manhattan's Zuccotti Park, a privately owned public space — a POPS, for short — legally controlled by Brookfield Office Properties. Unlike city-owned parks in New York, Zuccotti was open 24 hours a day, making it possible for protestors to camp out there.

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At the same time, Brookfield had broad leeway to set the rules for what kind of activity was allowed in the park, paving the way for New York police to clear protesters and their tents from Zuccotti.

In the case of the 24,000-square-foot Broad plaza, which will open this fall and connect the museum to a new apartment tower to the south being built by developer Related Cos., the complications have mostly to do with the peculiar way Grand Avenue has been physically remade over the last half-century.

The design by DS+R and Hood includes plans for 100-year-old olive trees flown in from Northern California and planted on two sides of a wide lawn. It puts a calm, even bucolic face on what turns out to be a remarkably complex slice of the urban realm.

To understand just how complex requires going back in time several decades to the 1960s, when L.A.'s Community Redevelopment Agency not only razed dozens of Victorian houses and apartment buildings on Bunker Hill but even trimmed off the top of the hill itself.

In the process the agency turned Grand Avenue, at the top of the newly engineered hill, into an odd double-decker street. Along lower Grand exists a part of the city largely shielded from public view and mostly meant for delivery trucks and drivers heading in or out of underground garages.

Along upper Grand, what appears at first glance like a normal urban boulevard is actually a long bridge, or cap, set atop lower Grand. That strange two-level infrastructure means that new buildings — like Diller, Scofidio + Renfro’s Broad museum — aren't constructed on upper Grand as much as they belly up to it.

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Creating a plaza in that location required building a giant elevated platform, anchored below along one block of General Thaddeus Kosciuszko Way, which connects to lower Grand. The platform is built like a small chunk of freeway overpass. The construction of the plaza, along with other streetscape improvements, has a price tag of $18 million. Roughly $10 million came from redevelopment funds and $8 million from the museum.

The new plaza will chip away, at least modestly, at the sense of isolation that has plagued Bunker Hill since it was redesigned a half-century ago. It will provide a new pedestrian connection from Grand to Hope Street, where a Regional Connector subway stop is due to open by 2020.