1908 
HUDSON & MANHATTAN TUBES  
The Hudson Terminal, completed in 1908, was a predecessor of the World Trade Center. The terminals of the twin tubes from New York to Jersey City were in two 22-story buildings, designed by architectural firm Clinton & Russell. They contained offices, shops, cafes, and a grand transit concourse, and they were the largest office structures in existence at the time.

1920s 
RADIO ROW AND A SIGN OF THINGS TO COME 
In the 1920s, a small warehouse district began to specialize in parts and equipment for the latest communications technology: radio.

The district eventually grew to encompass roughly 325 street-level stores, and an additional 1,000 businesses above street level, and bustled with people from all over the city. The area, which centered on Cortlandt Street, was a place of pilgrimage for the radio industry and was known as Radio Row.

1930s 
HUDSON TERMINAL

The original E-Train corridor connecting the current World Trade Center Oculus to the E-train was built circa 1930 and is the product of a series of dramatic changes and improvements to the city's transportation network.

Over the course of the 20th and 21st centuries, this corridor has connected the E Subway Line (originally part of what was known as the Independent Subway System, built in 1932) to four transportation hubs: the Hudson Terminal, the original World Trade Center, the temporary PATH station (opened 2003), and the current World Trade Center Oculus (opened 2016).

1940s 
A CONSOLIDATED SUBWAY BEGINS

When the subway opened in 1904, it became the preferred method of transportation for city dwellers, eclipsing all others. What began as a privately held nine-mile stretch of subway in Manhattan quickly evolved into three separate companies servicing New York City. In June 1940, the city decided to consolidate these companies and established the system in use today.

1961

SLURRY WALLS AND FOUNDATIONS

To build the World Trade Center, engineers had to devise a way to excavate and lay foundations on bedrock and around train tunnels without allowing water from the Hudson River to seep in. Their work contributed to four centuries of shoreline expansion with fill that has dramatically reshaped the boundaries of Lower Manhattan. Today, Greenwich Street roughly aligns with what was the original western shoreline of the 1600s.

The engineers' innovative solution, known as the slurry trench method, involved digging a deep trench while pumping in a thick mixture of water and clay to create a watertight seal. Eventually, the trench would be filled with concrete. After it was completed, the site became known as "the Bathtub."

Portions of the original slurry walls are featured in both the 9/11 Memorial Museum and Port Authority Trans-Hudson (PATH) World Trade Center Station. 

PORT AUTHORITY TRANS-HUDSON (PATH) OPENS

The Hudson & Manhattan Railroad was acquired by the Port Authority in 1962, following bankruptcy and years of plummeting ridership. The new owners decided that as part of the development of the World Trade Center, the Hudson Terminal Building would be replaced by larger and more modern buildings. The subsidized and improved railway was renamed the Port Authority Trans-Hudson (PATH).

April 4, 1973

TWIN TOWERS OPEN

When the Twin Towers opened in 1973, they were the tallest in the world, titans representing the city's might and ambition. They stood within the World Trade Center complex, a superblock that had its own zip code and occupied 16 acres of Lower Manhattan.

The complex was almost a city unto itself. At the time, it consisted of 12 million square feet of office space and an underground mall, home to some 80 stores and eateries. Eventually, 200,000 people would visit the site each weekday. When it was completed, the World Trade Center complex was criticized by some and lauded by others, but it indelibly altered the character of Lower Manhattan and the New York City skyline.