Blockchain technology—the foundation of cryptocurrency and other digital assets—is becoming more mainstream and alongside it, the explosive growth of non-fungible tokens (NFTs), whose own market value as per the estimates of Nikil Viswanathan, CEO of the blockchain company, Alchemy, has reached $1 billion, can no longer be ignored. But what are NFTs? And what is it about these red-hot commodities that have everyone from supermodel Kate Moss to billionaire Elon Musk cashing in? Here’s the primer.