Photo by Janice Boekhoff
Why is half of the Roman Colosseum missing?
The southern half of the outer wall of the Colosseum was brought down by an earthquake in 1349, but why just the southern portion? When geologists investigated, they found that a stream used to run through the area covered by the southern wall of the Colosseum. When the ancient Romans built the structure, they filled in the stream with loose soil. During the earthquake of 1349, the loose soil amplified the shock waves (much like ripples through water). Thus, the southern part of the structure recieved more sustained shaking–enough to bring down the outer wall–while the northern part, built on hard bedrock, absorbed the energy of the quake more quickly.
As in so many areas of life, it’s all about having strong foundations.
Source: Strip the City: Rome, Season 1, Episode 1 (aired on the Science Channel)