7 years old and 40 million guests: Airbnb is thriving
Founded in 2008, the home-sharing lodging site Airbnb has served 40 million guests — and, despite some horror stories, it’s clearly here to stay.
Polio vaccine at 60: triumphs, enduring battles and lessons
The discovery of the polio vaccine in 1955 and its success are relevant reminders in light of the recent measles outbreak.