What's left to do when you've been everywhere? Space tourism, of course: the final frontier.
People have been flying into space for centuries - at least in their minds and through science fiction. It is a respectable genre which dates back at least as far as Thomas More's 16-century Utopia and later, Gulliver's Travels by Jonathan Swift.
Science fiction really came into its own in the 20th century as science and inventions fired up our imaginations (and those of our parents and grandparents) through writers like Isaac Asimov and Arthur C. Clarke. And remember those comic books - Superman and Batman? Science fiction too.
Until very recently, private space flight was also science fiction, a fanciful flight of the imagination rather than body, certainly not anything we'd see in our lifetimes.
Astronauts would reach the stars. We common mortals would not.
All this changed in April 2001 when the world's first space tourist, an American businessman, spent a week on the International Space Station (at a modest cost of US$20 million).
I've always loved astronomy (I had a telescope at 12) and science fiction (When Worlds Collide was the first full-length adult book I ever read), but I'll leave the magic of suborbital flight to others since the mere mention of weightlessness makes my motion-sick self utterly queasy.
Today, private space flight is a reality. You can simply buy a ticket and hop into space - more or less.
Here are some of your space tourism options.
The main company ferrying space tourists is Space Adventures. It is the first company to organize trips for civilians to the International Space Station by Soviet Soyuz craft (they take about 3.5 hours to get there but lengthy months of training to qualify). Or you can fly into suborbital space, about ten times as high as a commercial jet for just over US$100,000.
Snapping at everyone's heels is Richard Branson's Virgin Galactic, which plans to become the world's first private space airline when it starts using its own spaceships to fly people 100 km into suborbital space from a dedicated base in New Mexico. A test flight crashed in late 2014 but that has only made Virgin redouble its efforts to deploy safe spacecraft.
The newest on the block is Blue Origin, the brainchild of Jeff Bezos of Amazon.com fame. A test rocket has launched successfully and the company has opened its waitlist for the New Shepard space vehicle, a rocket-fired capsule which will detach in space and parachute to the ground. Prices haven't been announced yet but... that's what the mailing list is for.
Another relative newcomer is World View Enterprises, which is planning near-space balloon flights in 2016 for US$75,000. They'll fly 30km up, or three times the altitude of a normal passenger aircraft.
There's also XCor Aerospace, at US$100,000 for a suborbital flight in its Lynx craft, and Elon Musk's SpaceX Dragon, the first commercial craft to ferry cargo to the space station and back; they're now working on a passenger vehicle.
If all of these are still a bit beyond what you'd like to invest, ZeroG offers a zero-gravity experience in a specially outfitted aircraft for a modest $5000 - space travel without the space, or the travel.
Just the sensation of being Supergirl or Wonder Woman for a while.
Tourism in space is still hugely expensive but money is being invested into this kind of travel. Also as more people sign up for flights - and they are lining up to do so - prices are bound to come down.
A few generations ago the final frontier was our atmosphere. Before that it was crossing the oceans.
Right now, it is space tourism.
What's next... time travel?
Would you travel in space if money were no object? What do you think of the idea?