The Shell Grotto is a picturesque cave around 100ft long, entirely adorned with shells. It was discovered in 1835 but to this day nobody knows when or why it was built. With no mentioning of it in any historic documents, we don't even know who created it. The grotto consists of the North passage you use to enter the grotto, the Rotunda, the Dome, the Serpentine Passage, and the Altar Chamber. From the moment you enter the Rotunda, you are in the presence of 4.6 million shells (wonder how long it took to collect them all). Of course, since the Grotto was opened to the public in 1838, and the site is too small to prevent visitors from touching the shells, there are signs of wear and tear throughout the site; however, this doesn't prevent you from enjoying the beauty of the site.
Although we do not know anything about its' purpose, and at this point, we will probably never get any real answers, I do think this is what draws people to this attraction. Because of its' unexplained existence, it is shrouded in mystery and I think that is what people find themselves drawn to. There is so much we know these days and very little in our world that is undiscovered. It's nice to go somewhere, experience it, ask your questions and ponder over your theories; all while you wander through its' chilly passages.