A recent report indicates that U.S. homelessness reached record levels last year, and today's show lists some of the reasons for the crisis. Also featured: junk food's impacts on the human brain and the biggest festival on Earth. In South Korea, a skyscraper's window washer confronts his fear of heights. And in Italy, a company walks dogs while their owners visit museums.

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Today's episode was sponsored by EF Educational Tours. Win a trip for up to 10 students and go anywhere EF travels for FREE! Please go to eftours.com/worldatoz by Feb 23rd.