You could say hydrogen was a bit of an enigma. It is the most common atom, comprising about 75% of the known matter in the universe in terms of mass.  If we're talking purely in terms of the number of atoms in the universe, the ratio is even more impressive, with hydrogen atoms comprising an estimated 90% of the total number of atoms.

The first Hydrogen Balloon being attacked by terrified French Villagers

From its discovery, the fact that hydrogen is the lightest element made it seemingly a perfect candidate for early air travel.  The first hydrogen ballloon was launched on 27 August 1783 from the Champ de Mars in France which is now the site of the Eiffel tower.  It took almost a quarter of a tonne of sulphuric acid, poured onto half a tonne of iron to produce enough hydroden to fill the 35 cubic meter baloon.  This had to be done over a number of days to fill it though lead pipes, due to the fact that the gas was hot when initially produced, but when it entered the balloon it cooled down and contracted in volume.

In less than 20 years from now, driven by the oil crisis and global warming, hydrogen could become an almost regular energy source in our daily lives, potentially being used to power anything from mobile phones to heating buildings and all the way through to our daily transport.