As one reader pointed out via Facebook, “There's a very nice building available at 46th and Market just now. Cheap, too.” Previous plans called for 4601 Market to become Philly police’s new headquarters, but with the move scrapped for another location, this historic behemoth is now up for grabs yet again.

Why it could work: The city already spent $50 million renovating the place, and its location right next to the 46th Street Station on the Market El-Frankford Line makes it highly accessible via public transportation. The site spans 15 acres.

Across the Schuylkill from University City is Grays Ferry, where University of Pennsylvania’s Pennovation center serves as the neighborhood’s newest anchor. Penn owns a 23-acre property here that it plans to build out in phases.

Why it could work: The area is considered one of the neighborhoods to watch this year, with property values still affordable. It’s located right off 76 and along the Schuylkill River Trail. The site where Pennovation sits also has a rich history as an industrial and research hub that dates back to the 1860s.

In a Curbed Philly poll, the Schuylkill Yards came out on top, with 37 percent of readers saying that the yet-to-be-built innovation hub should be home to Amazon’s HQ2. As one reader strongly put it, “Nothing except Schuylkill Yards means the city is putting its best foot forward. We would actively harm our chances by stealing from its limelight and marketing around an inferior site.”

Why it could work: The $3.5 billion mixed-use venture between Drexel University and Brandywine Realty Trust ticks off a lot of Amazon’s must-haves, including: 1) Location, since the future site is located right by Philly’s major transportation hub 30th Street Station; and 2) Additional space to build upon—it’s a 14-acre site with 6.9 million square feet of development planned and 6.5 acres of green space.

The Navy Yard is another obvious spot for Amazon’s new headquarters, garnering 26 percent of readers’ votes in a Curbed Philly poll. Since Urban Outfitters first moved its own HQ here years ago, dozens of other companies have moved to the campus, either converting old buildings and warehouses into their offices or building new offices from the ground up.

Why it could work: The massive campus on the Delaware River has plenty more space and land for Amazon to set up shop, and its location right next to a major U.S. port is another bonus. And while there are free shuttles from Center City to the Navy Yard, this could be the push needed to finally extend the Broad Street Line to the neighborhood.

Curbed readers weren’t the only ones to consider this neighborhood for Amazon’s HQ2. Benjamin’s Desk Chief Design Officer Adam Glaser told Technical.ly Philly that Callowhill is definitely an ideal location.

Why it could work: This long-overlooked neighborhood is ripe for development, with already a number of companies moving into the area’s abandoned warehouses and the Rail Park soon to open. In fact, Callowhill has been named Philly’s fast-emerging neighborhood, with lots of young professionals moving in and plenty of developable land up for grabs. It’s also easily accessible via the Broad Street Line and walkable to Center City.

In the Curbed Philly poll, North Philly came in third with 20 percent of the vote for Amazon’s new headquarters. One reader wrote, “Perfect location and cheaper than downtown and South Philly.”

Why it could work: North Broad is already undergoing some much-needed revitalization, and developers are eyeing areas up past Temple, where there are lots of abandoned warehouses and vacant land up for grabs. Its location makes it a prime spot for a transit-oriented mixed-use development, says Philadelphia 3.0.

One readers suggests going where Philly is already zoned for industrial: Northeast Philly. Old warehouses like the the Budd building in the Hunting Park neighborhood “might be a perfect location.”

Why it could work: As mentioned, this area at the edge of Philly is already zoned for industrial use, and there’s plenty of developable land for Amazon to expand in the future (the plant totals 20 buildings and 2.4 million square feet on 75 acres.) Although it is far from Center City, “the area is served by multiple bus lines and is close to the newly renovated Wayne Junction Regional rail station.”