The map shows the location of the Silk Road. A map titled Silk Road, circa 1st Century C E. A key shows the Main route of Silk R
oad with a green line and Other caravan routes with a purple line. It shows a scale from 1 to 1,000 kilometers. Green and purple lines cross the region. How does the map scale help to interpret the map? It shows how important silk was to European traders. It shows why the Silk Road was important only to China. It helps the reader understand how far traders had to travel. It shows the reader the difficult conditions on the Silk Road.
I would say that the answer is the Panama Canal. Even though construction began in 1904, it is the only canal I can think of which fits the description given.
The canal cuts across the isthmus of Panama and it connects the Atlantic and the Pacific Oceans.