If ever there were a gold star example of strategic social climbing at its very best, it was Alva Vanderbilt. While it may be difficult to imagine someone with such a surname as hers having trouble getting invited to parties, the Gilded Age was quite a different time. New Money was of no interest to Old Money, and the distasteful reputation of Cornelius Vanderbilt continued to color his descendants.

But the wife of William Kissam Vanderbilt, Cornelius’ grandson, had no interest in being passed over by the social set, instead, crafting a most ingenious plot to establish herself as New York's Queen Bee. Where today you may judge a socialite by her Instagram followers, in the late 1800s Mrs. Caroline Schermerhorn Astor was in charge of curating an actual annual social registry. Mrs. Astor's ballroom held 400 guests comfortably, and so each year 400 invitations were sent out to her annual ball - and let's just say if you weren't on the list, you might as well have moved abroad.

Though 400 may seem like a very large grand number, unsurprisingly Alva Vanderbilt still didn't make the cut. So in 1883, right after Petit Chateau was finished (her Gothic inspired Fifth Avenue home which took up the entire block between 51st and 52nd street), Alva got right to work on planning the party of the century.

1,200 invitations were sent out to her Masked Ball. But in true petty party girl style, Mrs. Astor's invitation was nowhere to be found. Eventually, Mrs. Astor's daughter, desperate to go to the soirée, had her go pay Mrs. Vanderbilt a visit. Following the hilariously catty excuse about how having never been invited to Mrs. Astor's home before, Alva had no address to send the invite, Mrs. Astor's pride was sufficiently bruised and she was officially invited.

On the evening of March 26th, onlookers gathered up and down Fifth Avenue to see the social circus as New York’s elite exited their carriages dressed as pharaohs, gypsies, pirates, goths, and perhaps my personal horribly creepy favorite, a cat. 

Miss Kate Fearing Strong came sporting a cat costume which featured a dress made of 17 real cat tails and a white taxidermy cat worn as a hat. 

Like, can you even!?! 

Rich people do the darnedest things...

All in, the costume ball ended up costing Alva around $250,000 ( which is basically equivalent to $6 million today). Quite the hefty amount when you reckon it was just so she could make some friends, no?

Before there was BFA, there was Mora, a Cuban refugee photographer who snapped shots of guests showing off their fanciful costumes. Besides the wonderful stories surrounding the evening - such as the third floor gymnasium which had been transformed into a forest of palm trees, bougainvilleas, and orchids, dinner prepared by the chefs at Delmonico's, which was served at two in the morning, and dancing quadrilles into the sunrise - it is Mora's photos which stand as treasures of and testaments to this most decadent moment in time.

Click through for a look at some of the best dressed guests! 

[Photos courtesy Museum of the City of New York, Library of Congress]