5 of the best unbuilt transportation projects in the 20th century

Worthwhile urban transportation infrastructure projects are ambitious, cost millions to make, and make it much easier to get from Point A to Point B. But for every transportation plan that makes it, there's another one that doesn't make the cut.

Here are some of the transportation projects that would have radically changed cities, if only they were completed.

Cincinnati wanted to have a subway.

While Cincinnati has a bike share and a bus system, it had real dreams for a subway at one point. 

According to the Verge, the city planned in 1916 for some 16 miles of subway lines to loop around the city. It would have been called the Rapid Transit Loop. 

The city only constructed seven miles of subway lines before the project was cancelled altogether ten years later due to a lack of funding followed by an economic downturn.

Today, only three abandoned subway lines remain.

There could have been an airport in the middle of London.

King's Cross is busy enough with a subway station in the geographic center of London, but imagine for a second how busy it would be with an airport.

In the 1930's, British architect Charles Glover had an idea for an elevated "aerodrome" at King's Cross, which would have been placed above the station's sidings. The aerodrome was imagined in the shape of a pinwheel with concrete runways to let airplanes shoot off in different directions out of the city. 

You can read more on the plans and see photos on the Guardian. 

New York had lots of subway extension ideas, including a subway connecting to Staten Island.

Today, New Yorkers know Staten Island as the one borough the train doesn't connect to. In 1923, the city broke ground on tunnels underneath the Verrazano-Narrows Bridge, but the tunnel only went on for 150 feet before being abandoned due to a lack of funding.

Unfortunately, the city missed the bus on making a subway line work. Today, Curbed writes, it would be prohibitively expensive to build a subway going Staten Island and purchase properties around the train line.