Beyond the answers - interesting background to this quiz

A gate that watched a city divide

The Brandenburg Gate in Berlin was completed in the late 18th century and long served as a symbol of the city. When the Berlin Wall went up in 1961, the gate found itself stranded in the restricted zone between East and West, and it became a backdrop for speeches and protests on both sides. After the wall fell in 1989, it turned into one of the most recognisable emblems of German reunification.

Thirteen days that gripped the world

The Cuban Missile Crisis unfolded in October 1962, after American reconnaissance flights revealed Soviet missile sites under construction in Cuba. President John F. Kennedy responded with a naval blockade, and for roughly two weeks the world watched as Washington and Moscow edged toward nuclear conflict. The standoff ended when the Soviet Union agreed to withdraw its missiles, in exchange for a US pledge not to invade Cuba and the quiet removal of American missiles from Turkey.

The planet with the wildest seasons

Mars has an axial tilt of about 25 degrees, close to Earth's, but its seasons are far more extreme. Its orbit is noticeably elliptical, so the planet's distance from the Sun varies a great deal over a single Martian year. That combination produces dramatic swings in temperature and weather, including dust storms that can sometimes shroud the entire planet.

Reading the periodic table

Chemical symbols often seem to ignore the English name, and lanthanum is a good example: its symbol is La, taken from the element's name itself. Several elements have symbols drawn from Latin or other languages instead, such as sodium (Na, from natrium) and iron (Fe, from ferrum). Learning these quirks makes the periodic table far less intimidating than it first appears.