Subjects include Christina Aguilera and the US space shuttle program.

Subjects include William Morris, Georges Remi and Tintin, and Torchwood.

The specialist subjects include the films of Judy Garland, The Cure and Hi-de-Hi!

Subjects include Michael Palin's travel documentaries, Lady Gaga and Emily Dickinson.

Subjects include Dear Evan Hansen, Elizabeth I and the feature films of David Lynch.

Subjects include Christopher Hitchens, Ayrton Senna and Killing Eve.

Subjects include Arnold Schwarzenegger, The Wire and the Falklands conflict.

Specialist subjects include Neil Armstrong, Shakespeare's comedies and Rupert Bear.

The specialist subjects include the wines of Portugal and Only Fools and Horses.

Subjects include Marie Curie, the BBC sitcom Ghosts, Elizabeth Woodville and Banksy.

Specialist subjects include Lewis Carroll, Detectorists and Sir Elton John.

In the third heat, subjects include Emily Wilding Davison and The Thick of It.

Subjects include the history of the Orkney Islands and Sir Garfield Sobers.

In the first heat of the series, subjects include Peaky Blinders and Francisco de Goya.

Subjects include the Peak District, Eleanor of Aquitaine and Open All Hours.

Specialist subjects include Jean Harlow, Porridge and Alexander the Great.

Specialist subjects include Pulp, Brian Clough and the Harry Potter novels.

Tonight’s semi-final subjects include Wilfred Owen, 20th-century boxing and Frasier.

Specialist subjects include the X-Files, York Minster and the Brooklyn Bridge.

Subjects include Vincent van Gogh’s paintings, the Bill & Ted films and drum and bass.

Specialist subjects include Formula One, Studio Ghibli films and Scott Pilgrim.

Specialist subjects include Grace Kelly and The Beatles' recording sessions.

Subjects include Joni Mitchell, the wives of Henry VIII and the films of Tom Cruise.

Subjects are Madonna, the ER character Doug Ross, the rivers of Yorkshire and the NHL.

Specialist subjects include White House pets, Edith Cavell and La Vuelta a España.