The explosion was heard across the Italian capital shortly after 8 a.m. local time and sent a huge cloud of dark smoke and fire that was visible from across the city.
With the Fourth of July falling on a Friday, Americans are taking advantage of the long weekend. AAA estimates 72 million people are traveling at least 50 miles for the holiday, which is 1.7 million more than last year. CBS News correspondent Nicole Valdes reports on air travel for the holiday weekend and how gas prices are contributing to the travel rush.
