The Khao Kheow Open Zoo was overrun with Moo Deng fans on the first of four days of activities marking the hippo’s birthday. Children under 12 years old can enter the zoo, about a two hour drive from the capital Bangkok, for free throughout the extravaganza. Many of Moo Deng’s fans flew miles to see her.

Thousands of fans have flocked to a Thailand zoo to celebrate the first birthday of Moo Deng, the baby pygmy hippo that's become a social media sensation.