Quantum liquids are unique states of matter that exhibit quantum mechanical properties on a macroscopic scale. They occur at extremely low temperatures, where particles behave collectively rather than individually. This leads to phenomena such as superfluidity, where a liquid can flow without viscosity, and superconductivity, where materials conduct electricity without resistance. One of the most studied examples of quantum liquids is helium-4, which becomes a superfluid below 2.17 Kelvin. In this state, it can climb walls and flow through tiny openings without losing energy. These behaviors challenge our classical understanding of liquids and reveal the fascinating world of quantum mechanics.