(The Sky Kingdom) After being pulled away in a storm on a hot air balloon, Pinkie Pie discovers a civilization of flying animal-pony hybrids on a series of floating islands off the coast of Equestria…

(Under Pressure) Applejack and Rainbow Dash fall into a sink hole in the jungle. They must escape a cavernous underground city of silence before rising water threatens to envelope them and the not-quite-dead inhabitants…

(High and Dry) Twilight Sparkle and Spike find a city half-underwater in the mountains where technology has advanced far beyond what either of them expected. They meet familiar aquatic ponies there…

(Golden Heart) The Mane Six find a golden city in the desert which is only visible when the sun hits it at the magic hour. They enter and discover Celestia’s foalhood home...and her ancient guardians…

(Colossal Mare Atlas) The Mane Six meet a colossus pony in the flattened lands. At over fifty meters tall, it houses an entire city of normal-sized ponies on framework around its sides and on its back…

(Initiate: Paradise) Twilight, Pinkie, and Rainbow Dash test out Canterlot’s new virtual tech system. When it turns on, they find themselves inside a virtual machine city and discover a new type of digital pony…

(Sleepwalk with Me) Apple Bloom is summoned to Princess Luna’s dream castle, but the Princess is trapped in her own ideal world. Apple Bloom must face Luna’s fears and her own if she wants to find the Princess…

(Ascension) Canterlot it suddenly transported to another planet. The inhabitants find another version of Canterlot there, but everyone is missing, except for one ancient alicorn who seems very familiar…

(Behold! Equusestria!) The Mane Six find an alternate universe where unicorns, earth ponies and pegasi all evolved differently, alicorns are not in charge, and strange new races roam the lands…

(Other) Write out your own “Lost World” idea in the comments! And hey, if you wanna write any fan fiction from these, feel free! Just link to it in the comments so we can read it later.