What are Crypto-collectibles or NFTs?

Crypto-collectibles or Non-Fungible-Tokens are digital objects resulting from the union between a token (such as BTC or ETH) and specific digital content. They are also known as augmented or improved tokens, since the traditional token, or cryptocoin, is linked to a digital content file (image, music, video, literature, etc.), giving it special properties and enhancing its value.
The special properties of NFTs include durability, scarcity, uniqueness, and transferability. It is also impossible to counterfeit them.