Importance of Water - Dirty and Clean: Water has both a societal and economical impact on countries around the world.
Revolution of Microelectronics Technology: Microelectronics are everywhere and it may even allow telepathy in the future, but however might cause more breaches of privacy.
Biomedical Engineering and Technology: The impurities in jewels actually make it change its colour which makes them known as the different ores we know now.
IT for Animation: 3D animation is cheaper than 2D and less labour intensive as well.
Disappearing glaciers, rising sea levels and why gravity is even more important than you think: Melting glaciers actually affect the countries further away from it as the rebound of the crust and less mass displaces the water.
The plenary session that left the deepest impression on me is IT for Animation. I like it because it makes animation sound more fun and not as labour intensive. It also can produce quite magnificent results.