In this presentation, we will explore the fascinating intersection of zero-knowledge proofs and blockchain technology. We will begin by demystifying zero-knowledge proofs, explaining their fundamental principles and tracing their evolution from theoretical primitives to practical tools in cryptography. Following this, we will delve into the world of blockchain, discussing its reliance on cryptographic techniques to ensure security and integrity. The core of the talk will focus on the necessity of zero-knowledge proofs in blockchain applications, addressing privacy and scalability concerns. We will highlight some applications of zero-knowledge proofs in the world of Blockchains.