NFTs, or non-fungible tokens, are unique digital assets that represent ownership of a specific item or piece of content, such as artwork, music, videos, or in-game items, on a blockchain. Unlike cryptocurrencies like Bitcoin, which are fungible and can be exchanged for one another, NFTs are unique and cannot be replaced or exchanged on a one-to-one basis. This uniqueness and the ability to prove ownership through blockchain technology make NFTs popular in the art and collectibles markets.