Georgia voters pick their next senator: Warnock or Walker

Voters in Georgia are heading back to the polls to decide the final Senate contest of the year, as Sen. Raphael Warnock faces Republican challenger Herschel Walker in a runoff. The Atlanta Journal-Constitution has been following both candidates’ campaigns.  Venice was recently saved from a flood by an engineering marvel. The Washington Post reports on the expensive barrier system — and warns that rising sea levels mean it is not a permanent solution. Taylor Swift fans are suing Ticketmaster after the presale for the singer’s upcoming tour crashed the site, leaving fans waiting for hours and many without the coveted tickets. The Verge has the story.  Bloomberg Businessweek breaks down how Duolingo distinguished itself by gamifying language-learning, and its struggles to to turn free users into paying customers.