The world of One Piece is is actually a world of islands connected by vast seas.
Bisecting the world is a large continent called the Red Line. The large sea that bypasses the Red Line is known as the Grand Line. (see pictures for clarity)
The Grand Line is home to unpredictable climate and currents that can change without notice. It requires a special item known as a Log Pose and a skilled navigator to even stand a chance. The Grand Line weeds out the weak and allows for only the worthy to survive its seas.
Like most action anime One Piece is full of people who posses superhuman abilities and powers.
Also the down side to consuming a devil fruit is that a person can no longer swim as they become dead weights in sea water. They are also vulnerable to sea stone as it negates the powers of devil fruits.
LOOK AND FEEL OF ONE PIECE
Many of the islands are in One Piece have distinct looks and feels. The Grand Line supports many different climates and as such there are many different islands.
The following are the main islands that are shown in the show and used in the different venues.
Arabasta is a desert kingdom that resembles Egypt. Both location posses vast desserts, pyramids, ruins, Palm trees, and scarce water reserves. In the story Arabasta is the site where Luffy defeats Crocodile and saves the kingdom.
Skypiea is a island that is literally in the sky. Clouds of different density are use in the construction of houses and roads. The island takes on the look of Heaven and the inhabitants are called Angles. There leader takes the title of "god" although he isn't actually a deity.
Water 7 is a large city/dry dock that builds boats and ships. The city's lower levels rise and fall with the tides. The city is littered with water canals and gondolas are used for primary navigation. The city's layout and architecture resembles Venice Italy.
Thriller Bark is a large "island ship" that houses Geko Moria.
The island is themed to look like a spooky ghost ship. The island has graveyards and an abandon mansion in the middle. The island's name is a reference to the Michel Jackson song "Thriller".
Sabaody Archipelago is a giant mangrove forest growing out of the ocean. Its trees produce bubbles that are ideal for using as storage and for coating ships for underwater passage.
Impel Down is an underwater prison that is used by the World Government. Its 5 levels each housing more and more dangerous criminals.
Marineford is the head base of operations for the Marines in the Grand Line. I houses thousands of soldiers and the Admirals. It is the place where Whitebeard and Luffy fight to save Ace. The base is set up as a giant horseshoe with a harbor in the middle.
