A permit filing with the city last week could indicate that big things are in motion at downtown’s long-neglected Gulch.

According to Bisnow, an anonymous permit was lodged to assess impact fees for a large parcel of land to the south of Philips Arena. The area has been in the news lately as rumors have swirled about a potential multi-billion dollar development backed by Atlanta sports moguls.

Now, the permit filing gives a glimpse at the potential impact such a development could have.

As proposed, the redevelopment could potentially bring office space totaling 9.3 million square feet—or more than half of all existing Class-A office space in Midtown, as Bisnow points out.

Beyond offices, the permit filing also includes 1 million square feet of commercial development, 2,100 apartments, and 1,500 hotel rooms.

In other words, a hypothetical downtown mini-city that would dwarf a fully built-out Atlantic Station, which is zoned for 6 million square feet total.

Coincidentally, or not, the proposal would fulfill all the needs outlined in the Amazon search for HQ2.

No further information is available about who filed documents for the mystery project—which would encompass land owned by the City of Atlanta and Norfolk Southern—or how realistic any development may be.

But the shear numbers in the filing demonstrate just how much potential The Gulch holds.