What do billionaires do in their past time? They come up with outrageous and seemingly impossible projects that could potentially change the world for better. In fact, some of these even sound like from a science fiction movie!

Jeff Bezos is backing construction of a giant clock inside a West Texas mountain, known as the 10,000 year clock. It will tick once per year for the next 100 centuries.

Elon Musk is developing a transportation system that would ping-pong people inside huge pneumatic tubes at 700 MPH.

Bill Gates and his wife are reinventing the toilet. In 2011, they've given grants to 16 research teams to find a sustainable sanitation solution for 2.5 billion people who don't have it.

Google co-founder Larry Page and Alphabet Inc Chairman Eric Schmidt have invested in Planetary Resources, a company aiming to land robots on asteroids in orbit between Mars and Jupiter and squeeze out fuel and minerals from the rocks.

PayPal co-founder and early Facebook investor Peter Thiel is a part of The Seasteading Institute, which is an organization with a mission to “establish permanent, autonomous ocean communities to enable experimentation and innovation with diverse social, political and legal systems.” Or basically... WATER WORLD.

Microsoft co-founder Paul Allen has the Allen Institute, an independent brain research center that works at better understanding grey matter in our skulls, and to treat diseases like Parkinson’s and Alzheimer’s.

Biotechnologist Craig Venter has set his sights on humans living to be 200 years old. Human Longevity Inc. is dedicated to preventing aging and diseases through harnessing genetic sequencing, or “extending the healthy, high performance human lifespan.”

Apple CEO Tim Cook invested in a showerhead that atomizes water droplets to produce more coverage while you bathe, cutting down how much water is used in a big way.

86-year-old Intel founder Gordon Moore has donated $200 million towards a GIANT 30 meter telescope capable of investigating whole new load of astrophysical questions. The telescope’s total budget is $1.4 billion.

Russian media mogul Dmitry Itskov founded the 2045 Initiative, and has assembled a team of 30 scientists to pioneer a multistage project that will slowly turn you into a biological robot. The last phase is set to be completed in 2045. Download your brain in to an avatar and become immortal.