1. Water anomaly: Water is unique in its molecular structure, exhibiting unusual properties such as its maximum density at 4°C. This means that water reaches its highest density at this temperature, unlike most substances, which reach their maximum density when they solidify. This phenomenon challenges conventional scientific understanding of how liquids behave.

2. Water memory: Some studies have suggested the possibility that water can “remember” substances it has been in contact with, even after extreme dilution. This challenges the principles of traditional physics and chemistry, as there is no clear explanation for how water could retain information about previous substances.

3. Structuring of water: There is evidence that water can form ordered structures at the molecular level, known as “clusters”. These structures can influence biological and chemical properties of water, challenging the conventional view that water is a homogeneous substance at the molecular level.

4. Therapeutic properties of water: Water is often associated with therapeutic properties in various cultures around the world, such as hydrotherapy and the belief in waters having healing powers. While many of these claims lack robust scientific evidence, there are still mysteries to be unraveled about how water can affect human health in ways beyond its known physical and chemical properties.

5. Anomalous behavior under extreme conditions: Under extreme conditions of temperature and pressure, water can exhibit surprising and poorly understood behaviors. For example, under certain conditions, water can become superfluid, flowing without friction and defying the laws of conventional physics. These phenomena challenge our current understanding of water and continue to be areas of active research in science.