Billionaires aren't just known for making a fortune on their innovative business ideas. They're also known for having eccentric and wild ideas that wouldn't normally seem possible. These are the same ideas that turn them into the billionaires they are today!

As an entrepreneur we face a lot of pushback from people on our ideas. For some of us, this is what drives us. For others, this can be crushing to our dreams. Despite all the negativity towards building our dreams, we all push through.

Even billionaires have to prove their ideas. Below are 11 of the craziest ideas from some of the world's most recognized names.

1. Clive Palmer's Titanic II

Clive Palmer, an Australian billionaire businessman who owns Mineralogy, had planned to build a replica of Titanic that would have cost $500 million. It was reported that the Titanic II would be unsinkable and would have approximately been 270m long, 50m high, and weighed about 40,000 tonnes. It also would have had 840 rooms and nine decks. However, it's been speculated that the project has since been shelved.

The Titanic II wasn't just the only bold idea that Palmer has attempted to make true. In 2013 he opened Palmersaurus, which was located at his Coolum resort in Queensland. The park featured more than 160 replica dinosaurs, which made it the largest dinosaur park in the world. It has since closed.

2. Dennis Tito's Mission to Mars

Engineer and founder of Wilshire Associates Dennis Tito announced in 2013 that he was working on making the 501-day trip to Mars a reality by 2018 when all of the planets are aligned, it appears to have been pushed back to 2021. The Inspiration Mars Foundation would include two members who would flyby Mars safely with the least amount of fuel possible. Even if it's just a flyby mission, the foundation could be on it's way to making space exploration for a mankind an actual possibility.

3. Yuri Milner's Global Brain

Tech investor Yuri Milner has made his fortune by getting in early on companies like Facebook, Groupon, and Zynga. In 2011, however, Milner believed that technology was only in it's infancy and that we're headed towards a "global brain." According to Milner, the global brain will consist 'of all the humans connected to each other and to the machine and interacting in a very unique and profound way, creating an intelligence that does not belong to any single human being or computer."

4. Bill Gates's War on Poverty

In the 2015 Gates Annual Letter, published by the Bill & Melinda Gates Foundation, the Microsoft founder stated that he believe within "the next 15 years will see major breakthroughs for most people in poor countries." While this idea is noble, it's a bit crazy to think that we could eliminate poverty.

This is because the foundation will use technology to improve healthcare and food production in developing parts of the world. Mobile banking will allow the poor to have bank accounts and exchange money. Finally, technology will improve education for those you couldn't normally have access or money to learn.

5. Peter Thiel's Floating Cities

There was a lot of buzz when PayPal co-founder Peter Thiel announced that he wanted to construct man-made islands that were free from government laws and regulations in 2008. The Seasteading Institute was appealing for entrepreneurs since they could work on their projects without having to be concerned with government interference.

Thiel is beginning to reconsider his original idea. It may be too expensive and unpredictable to have a city built in the middle of the ocean. That's why Thiel is looking to construct his floating cities in calmer waters, which will be regulated by the government.

6. Larry Page and Eric Schmidt Effort to Mine Asteroids

In 2012 Google's Larry Page and Eric Schmidt announced that they would be teaming up with filmmaker James Cameron to mine the asteroids that pass by Earth. The plan is for robotic ships to mine the asteroids for rare minerals like gold and platinum which are commonly used in electronics and batteries. The initial plan was to have telescopes built in order to scope out asteroids that are rich in minerals with a space station up and running by 2020.

7. Elon Musk's Hyperloop

If there is one billionaire who has turned his bold ideas into a reality it's Elon Musk; the man behind Tesla and SpaceX. Musk's latest pipe dream could revolutionize travel by allowing travelers to be propelled across the county in just a matter of hours.

As described by Wired, through above ground tubes, and with "extremely low air pressure inside those tubes, capsules filled with people would zip through them at near supersonic speeds." Construction for on a full-scale, passenger-ready Hyperloop is set to begin in 2016 between Los Angeles and San Francisco.

8. Jeff Bezos's 10,000-Year Clock

There are several misconceptions surrounding billionaire Jeff Bezos' so-called 10,000 Year Clock. While it was founded by the Amazon founder, it was also built on property that he owned, it's actually for a project for the Long Now foundation. The clock it powered by solar power, people, and a weight hanging on a gear - so it's not atomic. The idea behind the clock is to humble mankind. As noted in Business Insider:

"The clock is there to remind people that they are small when it comes down to it, and that most of our lives will last at the very most a fraction of 1% of the aspirational life of the clock. It's just another bold gesture that humanity has designed to give their descendants a sense of scale."

9. Dmitry Itskov Seeks Immortality

In 2013 Russian billionaire Dmitry Itskov laid out an ambitious for his Global Future 2045 conference; immortality.

Itskov's plan for the next step in human evolution by introducing robots that we can control with our brains by 2020. In 2025, we'll have the ability to transplant the brain into a life support system. The mind will then be able to move into a computer by 2035. Finally, in 2045, artificial brains will control insubstantial, hologram bodies.

Itskov isn't the only billionaire who are working on solving death. Google's Sergey Brin, Oracle's Larry Ellison, and Peter Nygard billionaire are also investing in research that could slow down the aging process.

10. Richard Branson's Virgin Galactic

Virgin Atlantic and Virgin Group billionaire Richard Branson has a history of attempting to break several world records, such as his "Virgin Atlantic Challenger." Was it really shocking when it was announced in 2004 that he has plans to take the average citizen into place?

Through Virgin Galactic, you can purchase a ticket into outer space for $250,000. That may sound like a hefty sum, but being able to join just 551 (give or take) other people who traveled above Earth's atmosphere is a once-in-a-lifetime journey.

11. Johan Huibers's Ark

In 1992 successful Dutch contractor Johan Huibers had a terrifying dream that his native homeland was flooded by the North Sea. In response, he began construction on a life-size replica of Noah's Ark in 2009 that measured approximately 30 meters wide, 23 meters high and 135 meters long. That's equivalent to a four-story building and the length of a football field!

The project cost $1.6 million and was completed in 2012. You can visit Johan's Ark on the Merwede River in the Dutch town of Dordrecht. While he isn't a billionaire, I find his story fascinating!

What are you building that will be worth a fortune in the future?