Beyond the answers - interesting background to this quiz

The element that hides in plain sight

Cobalt takes its name from the German word "kobold", meaning goblin or evil spirit. Medieval miners in Saxony blamed these underground creatures when ores they believed contained silver or copper instead yielded a stubborn substance that ruined their smelting. The element's symbol, Co, sits at atomic number 27, and today cobalt is essential to lithium-ion batteries and the deep blue pigments used in ceramics and glass.

A language with more speakers than Spain

Mexico's position as the world's largest Spanish-speaking country rests on a population of well over 120 million, far ahead of Colombia and Spain itself. The language arrived with Spanish colonisation after 1519, and over five centuries it has absorbed indigenous vocabulary, especially from Nahuatl, giving the world words like "chocolate", "tomato" and "avocado".

Why pure gold behaves so gently

Gold is a transition metal with a remarkably stable electron configuration, which is why it resists tarnishing and corrosion. In its pure form, measured on the Mohs scale, it ranks only around 2.5 to 3, softer than a copper coin. That softness is precisely why jewellers alloy it with silver, copper or palladium, and why 24-karat gold bends easily while 18-karat pieces hold their shape.

The symphony that changed everything

Beethoven completed his Fifth Symphony between 1804 and 1808, and its opening four-note motif became one of the most recognisable phrases in Western music. The work premiered in Vienna in December 1808 alongside the Sixth Symphony in a marathon concert. By then Beethoven was already losing his hearing, a decline that would become profound within a decade, yet he continued composing.

Water polo's long Olympic history

Water polo debuted at the 1900 Paris Olympics and has been contested at every Summer Games since, making it the oldest continuous team sport on the programme. Early matches, played in rivers and lakes, were far rougher than today's version. Hungary and Italy have dominated the men's competition, while women's water polo only joined the Olympic roster in 2000 in Sydney.