Here’s the crazy first game the creators of Pokémon Go made inside Google

In its first days, the new mobile game Pokémon Go is going gangbusters.

The app’s popularity comes from the popularity of the Nintendo franchise. It also likely stems from the game’s novelty: It lets you interact with the real world, using a smartphone as a guide in physical space.

Behind that novelty is Niantic Labs, the game’s co-creator, a skunkworks project created inside Google six years ago. It spun out of Google last fall, but has kept its core objective: Tapping the search giant’s massive mapping data for mobile games that co-mingle with the real world.

Niantic released its first multiplayer game, called Ingress, in 2012. It’s nuts.

Here’s my colleague Eric Johnson describing the basics two years ago:

Ingress assigns players into two teams, the Enlightened and the Resistance, and challenges them to venture out into the real world for what is essentially a massive global game of capture the flag. Players organize online and at in-person meetups, and Niantic Labs supplements the game with a regular stream of “news” about the war taking place in the game’s semi-imaginary world.

According to our sister site Polygon, much of the real-world data for Pokémon Go — where you find the cartoon characters to capture and what have you — comes from Ingress.

It wasn’t clear why Google parted ways with Niantic; its tech fits loosely into Google’s strategy for virtual and augmented reality. Niantic said Ingress has more than 14 million downloads — sizable, but not Google-sized. Still, Google put funds into Niantic’s $30 million round to build Pokémon Go.

This article originally appeared on Recode.net.