Corinth Canal in Greece is a very popular architectural attraction. It connects the Gulf of Corinth with the Saronic Gulf in the Aegean Sea. This canal is carved down into the rock. It is around 4 miles long and is only 70 feet wide at the base.
Melissani Cave, on Kefalonia Island in Greece, features a sky-blue lake within the cave. The lake is shallow and clear, and is covered with stones at the bottom. The cave was rediscovered in (In Greek mythology, Melissani was the cave of the nymphs.