Thessa's Birthday

Thessa's Birthday

Part of a series on Flash Mob Parties. [View Related Entries]

Updated Feb 04, 2014 at 01:20PM EST by James.

Added Jun 06, 2011 at 04:15PM EDT by Brad.

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Thessa’s Birthday was a Facebook event organized by Thessa K., a German teenager from Hamburg, Germany in June 2011. Although Thessa had planned on celebrating her birthday with friends and family members, thousands of Facebook users in Germany signed up for the open-invite event and around 1,500 people showed up at the listed address.


In May 2011, Thessa posted an event titled “Mein 16!” on Facebook[1]. The event was set as open-invitation and accessible to any users on Facebook, leading to over 15,000 RSVP confirmations by random users on the social networking site.

Prior to this event, the concept of Flashmob-style party crashing has been demonstrated through similar Facebook pranks seen elsewhere, including Kate’s Birthday and William Lashua’s Birthday in 2010.

Notable Developments

Viral RSVP on Facebook

According to the German online media blog MediaRauschen[9], Thessa’s Facebook event was cancelled after 2,500 RSVPs. However, dupcliate Facebook events with the girl’s real name, valid address and phone number were launched by others, providing unofficial venues to coordinate an epic flashmob party crash. The clone pages reached over 13,000 RSVPs by 10 a.m. on May 31st, but they were all deleted by noon. In response, some Facebook users launched an event at the lake adjacent to Thessa’s house and drew over 1,800 participants.

Flashmob Party

On May 31st, a Wordpress blog called PartyThessa[10] was launched to track the media coverage of the Facebook flashmob, but it soon came to an end with a post recommending all partygoers to stand down and send the girl a postcard instead:

In leading up to the day of event, German news publications and websites like Spiegel[1], Stern[2] and Die Welt[3] began reporting on the Flashmob party crashers, inviting more pranksters to add themselves to the guest list. On June 1st, the story quickly spread out of Germany, receiving international media coverage from TIME[4], AP[5] and Al-Jazeera[6] as well as blogs like The Daily What[7] and The Huffington Post[8].


On the day of Thessa’s birthday, at least 1500 people showed up at the sixteen year old’s Hamburg residence, which alerted the local police department to dispatch nearly 100 officers and cordon off Thessa’s house from the crowds.

The outdoor impromptu festival continued throughout the evening from 7 p.m. until 2 a.m. and many attendants brought signs and posters with congratulatory message for Thessa. According to the official statement, the party was mostly peaceful with exceptions of 11 people who were taken into custody for various indecent behaviors and misdemeanor charges. The birthday girl, however, did not make any appearance before the crowd, as she decided to spend the day at her grandparents’ home quietly.

Official Song

Search Interest

External References

[1]Facebook – now defunct

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