Engineers forgot to include underwear in the first U.S. spacesuits. This immediately became a problem.
We had no idea macaque monkeys could make humanlike sounds until we put them in an MRI scanner.
There were 12,989 heroin deaths in the U.S. in 2015. That's just slightly higher than the number of gun homicides, which totaled 12,979.
He was the first American to orbit Earth, and he holds the record for being the oldest person to travel in space.
The pill that prevents the contraction of HIV comes with plenty of barriers. Meet two people knocking them down in Chicago.
The city saw an intense spike in air pollution.