Which of these is not at sea level?

Sea-level canals are relatively simple artificial waterways that require no locks to change water levels. These are the answer options that refer to sea-level canals:

The Corinth Canal (pictured) cuts through the Isthmus of Corinth and connects the Gulf of Corinth in the Ionian Sea with the Saronic Gulf in the Aegean Sea.

The Grand Canal forms one of the major waterways within Venice and connects two parts of the Venice Lagoon.

The Suez Canal cuts through the Isthmus of Suez and connects the Mediterranean Sea to the Red Sea.

Unlike the Suez Canal, the Panama Canal is not at sea level. Instead, ships are raised and lowered by huge locks at either end, and pass through a freshwater channel.

The first of several French attempts to construct a canal through the then Colombian province of Panama began in 1881. The project was inspired by the diplomat Ferdinand de Lesseps, who was able to raise funds in France as a result of the profits generated by his successful construction of the Suez Canal. He had originally wanted a sea-level canal, like the Suez. But, although the Panama Canal needed to be only 40 percent as long as the Suez Canal, it was much more of an engineering challenge due to the combination of tropical rain forests, debilitating climate and the need for canal locks.

Eventually the project was taken over by the United States and completed in 1914 at a cost of about half a million dollars (equivalent to about thirteen billion dollars in 2022).