CryptoKitties

CryptoKitties is a blockchain game developed by Canadian studio Dapper Labs. The game allows players to buy, sell, and create non-fungible tokens (NFTs) using Ethereum. These NFTs represent virtual cats. The game's popularity in December 2017 congested the Ethereum network, causing it to reach an all-time high in the number of transactions and slowing it down significantly. Dapper Labs was spun-off from Axiom Zen. Both companies are based in Vancouver, Canada. CryptoKitties is the first major game to use blockchains, and one of the earliest examples of a blockchain project designed for recreation.