BASE jumping is a genuinely dangerous sport, only experienced parachutists can attempt it with an acceptable level of risk to their lives.
As a sport, jumping off a high vantage point like this has the most in common with free-fall parachuting.
It is nothing like paragliding.
The specially designed chute these guys use is rather similar to a sky diving parachute. It's just that the jumps are done off solid objects instead of from an aircraft!
Now here's something interesting. The very first parachute jump, in 1783, was actually a BASE jump! A very brave Frenchman, Louis-Sébastien Lenormand jumped from the tower of the Montpellier observatory. After that, most early parachute jumps were from balloons.
Why am I spelling it 'BASE' in big letters? Because it stands for
This name has been around since a film maker used it in 1978.
Sheer cliffs, water towers, skyscrapers, whatever is flat-sided and really tall tends to attract a BASE jumper!
Since distances and speeds are much smaller than in skydiving, specially designed gear is used to improve safety margins. But no reserve parachute is worn. There's just no point, since there would be no time to use it if something went wrong.
In contrast to all this, a paraglider pilot will most often launch from the side of a hill, or sometimes a downward-sloping ramp in mountainous areas. Firstly, the paraglider canopy is inflated and flown like a kite over the head of the pilot. Then the pilot simply walks or runs into the breeze until the ground drops away and the paraglider glides slowly away.
The pilot is then in charge of a true glider, being able to slow down, speed up and turn in either direction. Unlike jumping off a building or cliff, this person often has the option of gaining height by finding and flying through rising air. That's called soaring.
Paragliders are more lightly built than parachutes because they don't have to withstand the shock of suddenly opening at high speed. Also, the design of paragliders is more aerodynamically sophisticated since they are designed for maximum soaring performance.
I can remember someone doing a base jump here in Adelaide, South Australia, some years ago. He successfully leapt from the State Bank building. Can't remember if the police were waiting for him though.
Not all of these jumpers are reckless law breakers. Most are highly experienced skydivers who are just taking their sport to the next level. They know that their first accident might be their last, but have confidence in their own ability and experience. Sometimes, multiple jumps are organized, just like the group jumps done by skydivers.
Regarding the legalities, the actual act of jumping is not usually illegal. It's the trespassing, or other minor offences that can get jumpers into trouble. The big group jumps at the elite level, or day-long jumping events are usually well-organized, legal and draw sizable crowds.
Heard about the Irish parachute? It opens on impact... Just one example of my small collection of pathetic Irish jokes. My website stats don't show many people coming through here from Ireland, so I hope I get away with that. :-|
One final note on this remarkable sport. It's current public image is that of daredevils doing crazy, illegal and highly dangerous stunts. Apparently though, that image is gradually shifting to one where BASE jumping is seen as a genuine minor sport. Like paragliding or parachuting but more extreme, and with a somewhat higher level of risk.