What spice is the most essential and valuable commodity in the "Dune" universe?

More Questions:

How many squares are there on a standard Scrabble board?

Retsina is a wine traditionally made in which country?

As punishment for not appreciating Apollo's music, King Midas's ears were transformed into the ears of what animal?

Andorra is landlocked by what two countries?

The moons of Uranus are named after characters from the works of what writers?

What does the Binet-Simon scale measure?

What is the astronomical term for the distance light travels in a vacuum in one year?

What superhero is known as the "Caped Crusader"?

What year did Guns N" Roses release the album "The Spaghetti Incident"?

Which US president was born in Tampico, Illinois?

Which Saint was murdered at Canterbury Cathedral in 1170?

Which campaign was awarded the Nobel Peace Prize in 2017 for its work to promote the full implementation of the Treaty on Prohibition of Nuclear Weapons?

What is 2000 in Roman Numerals?

Who sang the song "Un-Break My Heart"?

What two Coaches on "The Voice" US have been on from season 1 through season 14?