“Originally,
the nebulous space with enhanced support pillars—which, when combined, carry a
weight of over one and a half million tonnes!

“Although
The Promenade is situated under twelve feet of solid rock, a pony could be
forgiven for thinking they were right outside,” 

Over the years, as our fair Princess Celestia forged peace between most every nation on the face of Equestria, however, the nigh-forgotten storage facility became home to a grey market, a trading hub for legal and illegal goods alike, hidden right under the noses of the guard. When their dealings were discovered several hundreds of years ago, the princess, in her infinite wisdom, decided that the time for fear of siege had passed, and ordered it turned into the wonderous place it is today.”