There's an alternate history of Manhattan in which there's no SoHo, no Little Italy as we know them. Broome Street is cast in shadow. Above it there's a highway: 10 lanes of Robert Moses' concrete.

This was the powerful and controversial master builder's Lower Manhattan Expressway, proposed by Moses before World War II to connect Brooklyn to Manhattan and the mainland, ultimately shot down by activists. A new free exhibit at City Hall looks back at the expressway and the fight to stop it.

But we know what destruction in the name of construction looks like on this scale. And we don't have to look in the history books. Just take the ride to Dead Horse Bay.

As outlined by a detailed and evocative ABC News feature, Dead Horse Bay has long been a locale for undesirables. Far from the city's center, where Brooklyn dips into Jamaica Bay, was an island home to only the dirtiest industries: fertilizer factories, garbage facilities and "horse rendering" -- hence the name.

The island was eventually connected to the rest of Brooklyn for the construction of Floyd Bennett Field. In the 1950s Moses decided to expand farther. So the garbage trucks began to roll in.

This was no ordinary landfill, however; it was debris and personal items from condemned homes destroyed in the name of Moses' "slum clearance" elsewhere in the borough. Poorly capped, the landfill didn't keep its secrets, and today you can find the tires, broken and intact glass bottles, nylons, toys and garbage of 60 years ago.

Dead Horse Bay is field-trip heaven for local schools. I remember going with a class in elementary school and being told not to cut ourselves on the glass. I think I found a horse bone. I don't remember the rangers telling us about Moses, probably because we were too young for the doom and gloom of bulldozers and the banalities of council committee chairmanships and proxy votes.

It's a shame that we students didn't know anything about him, though, because he shaped our entire world, from the Belt Parkway to the Prospect Expressway, Riis Park to Jones Beach.

Instead we messed around in somebody else's trash.

Mark Chiusano is an editorial writer for amNew York.