Adventure Week

The Adventure Week is an event in Pokémon GO that occurs in the latter-half of May.

Features
During this event, more items were awarded from every PokéStop, and Poké Balls were 50% off in the in-game Shop. Buddy Pokémon found Candies four times as fast for the duration of the celebration. Additionally, an all-new avatar item became available in the wardrobe &mdash; the Explorer's Hat.

Event Pokémon
Following Rock-type Pokémon, known in player community as the "Fossil Pokémon" had increased spawnrate in the wild.

Trivia

 * In event announcement, Niantic mentioned few statistics:
 * Back in December, 2016, Trainers collectively walked past the equivalent distance of Earth to Pluto.
 * As of May, 2016, the Pokémon GO community has traveled more than 15.8 billion kilometers.