An offensive tweet about AIDS in Africa created a firestorm over the weekend and ultimately cost public relations executive Justine Sacco her job. Check out eight lives changed by the popular microblogging site.
Ashleigh Stumler thought she was getting dizzy as she hiked in the thin air of Mount Everest. But a guide told her it was something else. An earthquake was roiling Nepal and shaking the world's tallest mountain to its roots.