Karagol Sea

The Karagol Sea is located between Tolbi and Kalay. Although called a sea, it is actually landlocked, and so is more accurately thought of as a great salt lake or inland sea.

The Karagol is completely surrounded by the continent of Angara, though beyond a river just south of the sea is the southern continent of Gondowan. These two continents seem to represent Eurasia and Africa respectively, it is likely that the Karagol Sea is based on the Mediterranean Sea. Perhaps the most notable feature of the Karagol Seas is the small, uncharted island located within.

There are several land-based routes around the Karagol Sea, all of which are initally blocked, forcing the player to use a boat to reach Tolbi.
 * The longest route begins north of Tolbi, whereupon one must traverse to the eastern shore of Angara and follow it south, through Mogall Forest to Xian, whereupon they would normally be able to return to Tolbi via Silk Road (although this is blocked throughout Golden Sun). Due to the bridge which is broken as soon as the player approaches Vault, this route is blocked until after the events at Colosso.
 * Silk Road itself is a route that circumnavigates the north shore of the Karagol and acts as a trade route between Xian and Tolbi, which passes by Altin and through Kalay. This route is actually impassable at two points during the course of Golden Sun, as two separate landslides block the road. One can be cleared (or traversed around, by going through Altin Peak) and is located at the Alpine Crossing. However, the other landslide, located north of Kalay Docks, renders the route impassable for the entirety of the game.
 * The final route begins south of the Karagol Sea, and is possible to traverse through after completing a small dungeon-like cavern, called Gondowan Cave. This route can only be unblocked from the Tolbi-side of the sea, hence allowing the player to return to Kalay, but not to skip the passage on the Tolbi-bound Ship.

Story
After Mt. Aleph's eruption in the beginning of the game, the Karagol, normally a sea placid enough for regular ferry runs between Kalay and Tolbi, rapidly becomes a dangerous and hostile area. The boats that usually travel the sea are attacked frequently, to the point that, despite the large influx of tourists wishing to see Colosso and the blockage of the Silk Road land route, the sailors become extremely reluctant to set sail. Eventually, Isaac's chase across Weyard brings him to the shores of the Karagol, only to find that there is no possible way of getting to the other side without taking a ship across, so his party joined up with a group of tourists and bought tickets on the Tolbi-bound Ship. However, due to a small sailor revolt, setting sail proves no easy task. Isaac's party, along with the warriors Sean and Ouranos, has to agree to work as bodyguards to protect the various passengers and crew, which they are happy to do. But this is not all, as the superstitious Capitan refuses to set sail without his lucky Anchor Charm which is stolen by a sailor fearful of returning to the sea.

After finding this charm and vowing to protect the oarsmen, Isaac's party finally sets out to sea, only to be attacked by various monsters, the greatest of which is a mighty Kraken, which manages to defeat both Sean and Ouranos before being slain by the party of Adepts. Eventually, the boat does manage to reach Tolbi, but the ordeal proves too great for the ship's Capitan and he decides to make the trip a one-way voyage, fearful that he too will meet the fate of his Ferry's replacement ship, which was lost en route to Kalay. As of the end of Golden Sun, no boats dare run across the now infamous Karagol Sea.

Trivia

 * The music that plays on the Tolbi-bound Ship while crossing the Karagol Sea was used for an E3 teaser trailer of Golden Sun DS in June of 2009.
 * In Animal Crossing for the GCN, Gulliver sometimes mentions he found the item he gives the player from the Karagol Sea.