Short answers, pulled from the story.
Helium was first discovered on the 18th of August 1868 during a total solar eclipse over the Malacca peninsula by French astronomer Jules Janssen. English astronomer Norman Lockyer independently observed the same spectral signature from Britain and named the element after the Greek word helios for the Sun.
The first terrestrial isolation of helium occurred on the 26th of March 1895 when Scottish chemist Sir William Ramsay treated the mineral cleveite with mineral acids. This discovery proved that the element existed on Earth after remaining a cosmic curiosity for nearly three decades.
Helium remains liquid down to absolute zero at atmospheric pressure and exhibits two distinct liquid phases known as Helium I and Helium II. Helium II is a superfluid that exhibits zero viscosity and can flow through capillaries as thin as 10 to 100 nanometers without resistance.
Helium was considered a strategic resource because the Helium Act of 1925 banned its export and the United States government established the National Helium Reserve in 1925 at Amarillo, Texas. This reserve ensured a supply for military airships during war and commercial airships in peacetime while helium was required as a coolant to create oxygen-hydrogen rocket fuel during the Space Race.
Helium-4 constitutes 24% of the total elemental mass of the observable universe because its nucleus is identical to an alpha particle and was formed in enormous quantities during Big Bang nucleosynthesis. The nuclear binding energy of helium-4 is so high that it prevents the formation of heavier elements in the early universe.
Inhaling helium can be fatal because the gas displaces oxygen needed for normal respiration and can cause barotrauma that fatally ruptures lung tissue. The largest single use of liquid helium is to cool the superconducting magnets in modern MRI scanners and the Large Hadron Collider at CERN.