The Great Blue Hole is a massive underwater sinkhole off the coast of Belize. In the winter of 2018, a submarine crew from Aquatica Submarines ventured to the bottom of the hole and made some unexpected discoveries.
The Corinth Canal connects the Gulf of Corinth with the Saronic Gulf in the Aegean Sea. It cuts through the narrow Isthmus of Corinth and separates the Peloponnese from the Greek mainland, arguably making the peninsula an island. The canal was dug through the Isthmus at sea level and has no locks.
