The letter Z has become a symbol of support for Russia’s invasion of Ukraine, appearing on T-shirts, billboards and social media accounts in defense of the war. Now, some European countries have decided to ban public displays of the letter altogether. And Twitter is one of the world's most influential public spaces. Its purchase by Elon Musk, who calls himself a “free speech absolutist” is likely to shake up Twitter’s role on the global stage. Plus, the oldest-known person in the world, Kane Tanaka of Japan, has died at the age of 119.