Floating Island

Floating Islands and Floating Lakes are located generally well above the world's main land mass and can be found all the way up to Space. Their location makes them susceptible to Harpies in pre-hardmode, Wyverns and in Hardmode. Being at such high altitude, players often experience reduced gravity when navigating them. Both are similar in size and placement, and both rest atop Cloud and Rain Cloud blocks with background Cloud Walls.

Floating Island
A Floating Island contains a mass of isolated Forest land and a house-like structure. Each world will contain at least one Floating Island, up to a possible eight maximum in large worlds. Floating Islands will usually contain a structure constructed from Sunplate Block, Disc Wall, and Glass Wall. It will always contain exactly one Skyware Chest along with other random Skyware furniture. Each Skyware Chest contains either a Lucky Horseshoe, Starfury, Shiny Red Balloon, or, along with other typical Forest chest loot. Unique items are chosen at random, with the restriction that all four unique items must be spawned at least once before truly random unique items spawn on any remaining Islands.

Floating Lake
Floating Lakes consist of nothing more than a large body of water, suitable for Fishing. There will be relatively few of these in a world. Unlike Floating Islands, they do not have Sunplate Block structures, or any of their contents. Some exclusive catches can be found there, like the Damselfish, Sky Crates and some quest fish including sky-exclusive Cloudfish.

Floating Lakes can rarely contain Water Chests.

Tips

 * Floating Islands can be located using a long-range weapon with a ricocheting projectile, such as the Water Bolt. The projectile's return will signify a landmass above.
 * A bow can help locate islands as well, if the player shoots straight upwards with a high-velocity arrow; if only some arrows return, there is a sky island. (This only works on small worlds due to the height of the islands in larger worlds.)
 * Gravitation Potions make locating and accessing Floating Islands much easier.
 * Floating Islands will catch Fallen Stars. Areas on the surface in which Fallen Stars rarely or never fall may have a Floating Island above.
 * Sometimes sky islands generate over dungeons, making them easy to get to using wings or rocket boots, and a grappling hook.
 * A Gravity Globe can be quite helpful, as it provides endless gravitation.
 * To protect any Floating Islands or Floating Lakes from meteors, place a chest 25 blocks from either edge of the island.
 * The UFO Mount allows for endless flight, and makes finding Floating Islands easy.
 * One way to find floating islands is to create a Hardcore character, die and become a Ghost, and then fly around to look for one. Once you have found one, you can log back in to your main character and navigate to it.
 * Another way to find floating islands is to go up to the height where floating islands are typically found, then create a temporary skybridge using the Ice Rod.
 * It is possible to locate a floating island via a water fountain falling low enough to been seen when flying.

Trivia

 * Floating Islands were originally made out of Dirt and Stone Blocks. The house was either made of Gold, Silver or Copper Bricks with a single Gold Chest inside, causing it to resemble a shrine. Grass vines hanging below the island could be used to locate it as projectiles would make noise when destroying them.

History
Fliegende Insel Île Flottante 漂浮岛