No, you're not going crazy. There really are thousands of Santa Clauses riding the subway, crowding the bars and landmark-hopping all around your city today.

In fact, the annual SantaCon event is happening in 37 countries across 275 locations on Saturday, from New York City and San Francisco to London, Hong Kong, Syndey and Hong Kong. (Other U.S. cities include Miami, Austin and Milwaukee).

For those unfamiliar with the phenomenon, participants dress up as Santa — or other seasonal costumes such as an elf or candy cane — for a massive bar crawl. This means, of course, swarms of people are traveling in packs ... and drinking. Hello, visual stimulation.

The Santas are encouraged to follow along on Twitter (@SantaCon) to find out the latest meet-up spots and use the hashtag #SantaCon, which is currently trending nationwide.

Here's a look at a few pictures posted to Twitter and Instagram that capture the essence of the day:

The internet is a force for both good and evil. And then there's #SANTACON twitter.com/TimKarr/status… — TimKarr (@TimKarr) December 15, 2012

And if the holidays aren't your thing, there's also an annual PirateCon and BunnyCon too.

Have any pictures from SantaCon? Share the links in the comments below.

Image via SantaCon.info