At its earliest stages it is difficult if not impossible to differentiate between what we now regard as being two entirely different aspects of non-powered flight using wings and weight-shift designs
The very earliest more or less successful attempts were basically primitive hang gliders, going back at least to the 10th century in Spain, in Cordoba. The monk Eilmer seems to have done quite well at MALMESBURY around the early years of the 11th century. Since then, most attempts resulted in a 1:1 glide ratio with usually fatal results, until the mid nineteenth century.
THE FIRST GLIDER?
It would appear that the first person to design a practical glider, capable of carrying a person, was Sir George Cayley who, circa 1853, designed at least two 'machines' which flew really quite well, albiet being launched along a downward slope. Sir George didn't decide to fly, instead he nominated a boy, and a bit later his coachman. The latter resigning on the spot.
It is often repeated that Otto Lilienthal was the first man to seriously advance the glider idea. But perhaps he wasn't, his designs which performed some 2000 flights between 1891 and 1896 when he died in a crash, were weight-shift designs. Not gliders at all, as we now consider the concept? But then again, what exactly constitutes a glider? Perhaps one definition might be an un-powered aircraft with the means of control confined to the pilot pulling on levers to make changes to the lifting surfaces? In order to effect the behaviour of the 'machine' - as aircraft where usually described in those days.
Around the turn of the twentieth century the Wright Brothers in America and Percy Pilcher in the UK, (amongst others), were making great strides in designing what we can now regard as a practical glider, except that they didn't glide very well. But it was a start.
Without any doubt it was the Germans, after WW1 and being prohibited from building aeroplanes, who really advanced glider design - a tradition they still value very highly today.
THE FINEST FORM OF AVIATION?
In so many ways gliding really is the very best way of pure flying. And modern gliders are outstanding examples of what can be achieved in aerodynamic efficiency. It takes far more experience and knowledge to get the best out of a glider, than learning to bore holes in the sky behind an engine.
THE RECORDS (Up to 2019)
As far as I can make out, (and I might well be wrong - records keep getting broken of course), the longest flight in a glider was 1865 miles (3008km) set in 2003.
The height record is 76,122ft (23,202m), albiet in a very special type designed for the task. This said, regular advanced designs can easily go up to 30,000ft and above with the pilot equipped with an oxygen supply.
The duration record, it seems, is 57 hours 10 minutes.
Speed. Unlike powered aircraft, for gliders speed is, it might appear, of little if any importance. Not so. Obviously no glider will get anywhere near going supersonic. But to obtain records, speed is often of the utmost importance - indeed every extra knot counts.
This said, they can travel a heck of a lot faster than might be imagined. As far as I can make-out, the fastest can attain 155 knots (180 mph).
I have no idea at all how this might fluctuate in recent decades, but the trend over time definitely indicates that gliding has become increasingly popular. And, for very good reasons. Firstly, at a base level, it is quite affordable to most people, and the sheer joy of being aloft in a glider is an experience hard to beat. And I say this as somebody who is a huge fan of sitting behind a mechanical donkey propelling me through the sky.
The other aspect is that anybody getting involved with gliding, can if they wish, set themselves ever increasing tasks of a multitude of challenging circumstances, in which experience and ability pays dividends. The better you become the further you can fly, or the longer you can fly, or both. For me at least it also has another huge attraction, you can do this, unlike most other sports, sitting down! Usually in an attitude which is the next best thing to lying down. Does it get any better?
Also, the physical demands of gliding are fairly minimal usually, but you can get extra exertion by helping to position gliders by hand. So - another win-win combination to recommend gliding. Also, equally important in todays world, is that your 'carbon-footprint' will also be quite minimal, even with aero-tows.
This said, being confined to a very, very small space for hours on end, seeking to better even your own height, endurance and distance records, really does demand a considerable degree of physical fitness. It is no easy task, and of course mental alertness is needed throughout.
Without any doubt the future of gliding is very bright indeed. It ticks so many boxes, and even the most dedicated enthusiasts can never be satisfied. There is always that next record to be broken. And, even today, if proof is needed, just look at major gliding competitions, the sheer amount of competitors presents a fabulous spectacle unequalled at any other aviation event.