The World Trade Center slurry wall survived the September 11 attacks to become an iconic reminder of a nation's loss and resolve. Test your knowledge of this unique structure with our quiz.
The slurry wall was built in 1967.
The slurry wall was designed to keep the World Trade Center's basement from flooding.
The slurry trench method for building an underground wall was developed in Italy.
The slurry trench method was developed in the late 1940s.
The first proposed location of the World Trade Center was on the Lower East Side.
The Port of New York Authority built the World Trade Center.
The slurry wall is 3 feet (0.9 meters) thick.
Clay and water were the ingredients in the slurry.
The consistency of the slurry usually is compared to buttermilk.
The World Trade Center was built on a landfill.
The neighborhood where the Twin Towers were built previously was known as Radio Row.
The clay used in the slurry wall came from Wyoming.
The slurry was used to keep water from seeping into the trench and collapsing its walls.
At the deepest point, the slurry trench reached down about 80 feet (24 meters) into the bedrock.
After the trench was completed, concrete was pumped into the trench to form the actual wall.
The museum construction budget allocated $11 million for preserving and restoring the wall.
Three 20-foot-wide (6-meter-wide) panels of the wall were included.
Steel cables now support the slurry wall from the interior, instead of the Twin Towers' basement.
A thin layer of concrete called "shotcrete" was applied to the wall's surface to preserve it.
If the slurry wall had collapsed, New York's subways might have flooded.