On May 10, 2017, actor and activist Leonardo DiCaprio took to Twitter to save a marine species.

"The vaquita is the most endangered marine mammal in the world," he wrote of the species, which can only be found off Mexico's shores in the Gulf of California. "Join me [and the World Wildlife Fund] and take action."

It may seem like an average tweet, coming from one of the biggest environmental advocates in the world. But the tweet has had global ramifications.

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