The Mediterranean Sea is the first level in Tomb Raider: Underworld. Lara Croft is on her yacht and speaks with Zip and Alister Fletcher on a laptop in a cut scene explaining the mission. You then dive into the sea and continue downward to an underwater ruin with some shark enemies. Once inside the ruins you find the infamous Kraken from the Underworld trailers, however in a cut scene it is revealed that the Kraken is in fact blind and it does not attack Lara unless you swim very close to it.
The Kraken is easily defeated through a simple mechanism puzzle. This proceeds to Lara getting the first of Thor's equipment, a Gauntlet. Mercenaries follow Lara, knock her out and take the Gauntlet. Lara then leaves the ruins and swims back to her yacht and goes to Evert's ship. These are the first human enemies Lara encounters. This is also a good place to unlock the Grenadier and Master Grenadier achievements for Xbox 360. Once inside the ship it begins to sink after a mercenary accidentally shoots a fuel tank. This is when you meet Amanda and Jacqueline Natla for the first time. Natla tells Lara that her search should involve Coastal Thailand. Lara then has to escape the sinking ship. Once outside the ship Amanda throws the Gauntlet into the sea after being told by Natla that it will only fit Lara's hand. Lara then dives in to retrieve it and the level ends.