This is SCIENCE FRIDAY, I'm Ira Flatow. He's been called Mayor McSchwinn for riding his bicycle to work. He's pledged to turn his town of Seattle into a model for what one city can do to lower its carbon footprint, and for good reason. As the climate changes, coastal cities like Seattle are challenged by rising sea levels.
We are broadcasting today from the Pacific Science Center in Seattle. And just steps away from this building, right outside is something that should be familiar to anyone who's ever received a postcard from Seattle or taken home a pen or a glass or anything tchotchke of any kind. And it's the Space Needle, built in connection with the 1962 World's Fair. It is an iconic part of the Seattle skyline.
Look through a series of 15th-century woodcuts, and you'll find that the leper is as much an icon of medieval art as the crown or the cross.
Leprosy was so common in Europe during the Middle Ages that it's estimated 1 in 30 people was infected with the bacteria. But by the turn of the 16th century, after the Crusades had swept across Europe, the disease mysteriously disappeared. And it never returned.
This left scientists puzzled. Did the bacteria mutate to become less harmful, or did Europeans become resistant to the germs?