Misc: This ancient attempt to transmute base metals into gold was called ?

Questions

Meursault, the title character in Albert Camus' famous novel The Stranger, had a first name what was mentioned only in Camus' personal journals, what was it?

Mexico City is sinking at a rate of 6 to 8 inches a year because its built on top of what?

if a plane crashes on the border where do they bury the survivors?

voiceless it cries, wingless it flutters, toothless it bites, mouthless it mutters?

what has 3 feet but can not walk?