Welcome back to Curbed's Could Have Been, where we investigate some of the most outlandish proposals that were never built. Know of a plan that never saw the light of day? Send it to the tipline.

In the early 20th century, land reclamation was such a popular idea that at least once a decade, some engineer proposed filling in a New York waterway to make the city bigger and better. There was the 1934 plan to turn the Hudson River into land, which came 10 years after a plan to drain the East River. But both of those bonkers plans were preceded by an even more ambitious scheme, put forth by a Dr. T. Kennard Thomson in a 1916 issue of Popular Science. Not only did he want to fill in the East River, but the plan also called for creating a "New Manhattan" to the south that would subsume Governors and Liberty Islands. He also wanted to build new islands and tack new land onto Staten Island and New Jersey for a total of 50 square miles with 100 miles of new waterfront property.

Thompson was no crackpot engineer with fanciful ideas. He designed and built pneumatic caissons (water-tight supports) for dozens of bridges across the country, consulted on more than 20 New York skyscrapers by 1916, and helped create the New York barge canal system. Even still, he admits in the first paragraph of the Popular Science article that his new landmass idea "seems somewhat stupendous," but he was convinced that creating new land and more shipping areas would ease congestion both on land and in the harbor.

Through his proposal, City Hall would become the literal center of the city, with a radius of surrounding land stretching for 25 miles. "...Within that circle, there would be ample room for a population of twenty-five millions," wrote Thompson. The whole thing would take "a few years," and supposedly hundreds of engineers supported his proposal.

The cost would be "a great deal more than the sum involved in the construction of the Panama Canal," but Thompson believe that "the great returns would quickly pay off the debt incurred, and then would commence to swell the city's money bags until New York would be the richest city in the world." The Panama Canal cost the U.S. about $375 million, and Thompson's endeavor would require "an annual expenditure" of $50 to $100 million. By today's numbers, that's a hefty amount more than $1 billion every year.

The plan would be carried out in phases, the first of which would be to extend Manhattan from the Battery to within one mile of Staten Island. Then the boroughs would be connected with new subway tunnels, which Thompson said would increase the value of Staten Island from $50 million to $500 million. Next, a large island would be built off the shore of Sandy Hook, which would protect a "new harbor" created by the addition of two new pieces of land jutting off Staten Island. The point? To create 40 miles of new docks, shipyards, dry docks, and coaling stations that could accommodate the biggest ships in the world.

After that, the East River would be wiped out. "Naval authorities agree that the East River is no place for the Brooklyn Navy Yard," wrote Thompson. The Navy Yard would move to new land in Newark Bay, and a new East River would be cut through Brooklyn and Queens, connecting the Flushing and Jamaica Bays. A new Harlem River would be created as well, slicing through upper Manhattan from Hell Gate to the Hudson River. The old East River would be filled in, upon which new highways and "business blocks" like Grand Central's Terminal City would be built. And of course, more subways would run beneath the new acreage.

Obviously, his plan never came to be. By 1930, Thompson must have realized his ambitious ideas would never become a reality, and he drastically scaled back the plan to include only the "New Manhattan." Instead of filling in the East River, he proposed fusing the new island to New Jersey and creating a Four Mile Boulevard with three tiers, one each for car, trains, and planes. But given that New York's harbor looks much the same as it did when Thompson dreamt up his scheme, we all know how this story ends.

· A Really Greater New York [Popular Science via Google Books]

· 1916 Plan for NYC Proposed Fusing Brooklyn and Manhattan, Building New Islands [io9]

· 486 - "A Really Greater New York" [Strange Maps on Big Think]

· Curbed's Could Have Been archives [Curbed]