Is it still considered archaeology when you're looking for human artifacts underwater? It sure is! It's known as marine or maritime archaeology. Marine archaeology is its own area of study due to its unique nature.
A marine archaeology excavation brings with it issues and challenges unique to being at the bottom of the ocean. For one thing, people can only dive so deep. For some wrecks, notably that of the RMS Titanic, remote controlled robots were used instead of fragile humans. The seafloor is a very dangerous place, it is also quite cold down there.
A brave robot, exploring the wreck of the RMS Titanic.
Artifacts and ruins left underwater are quickly covered in marine life.
“Remote controlled robots were used instead of fragile humans”
According to the UNESCO World Heritage site, "the city of Tiwanaku, capital of a powerful pre-Hispanic empire that dominated a large area of the southern Andes and beyond, reached its apogee between 500 and 900 AD."
Just read great article by Joe West at Indiana State University. He and his team might have solved the mystery of how the Pyramids of Giza were (or should have been) built! West and his team did terrific research on Dodecagons.
This is an ancient wall complex in Machu Picchu, Peru. It took more than 100 years to complete, with rocks that weigh hundreds of tons. The fortress spans for 600 meters, and was the largest structure the Incas built.