Which leader declared himself the first Tsar of Russia in 1547?

Ivan IV (Ivan the Terrible)

What Christmas decoration do spiders symbolize in Ukrainian tradition? Which mammal emits unpleasant musky odors from glands near its tail when threatened? What sweet substance is made by boiling sugar and water? Who signed the Treaty of Nanjing to end the First Opium War? What is the traditional candy-coated chocolate egg in the UK called?