Not to endlessly harp on the whole DC-needs-skyscrapers thing but it seems noteworthy that a developer just agreed to pay $109 million for the right to build a deck over I-395 and then put buildings on it. That’s an awful lot of money. And it’s for the last substantial buildable parcel in the central business district. And in fact it takes a pretty generous construal of “central business district” to say the I-395 trench even qualifies. That just goes to show how scarce and in-demand centrally located land is right now.