A mid-air crash of two helicopters in Rio de Janeiro killed six people, including U.S. singer Oliver Tree and Argentine YouTuber Gaspar Prim.

<p> <img alt="All the victims were traveling in the aircraft. Among them were US singer Oliver Tree and Argentine YouTuber Gaspar Prim, known as Gaspi." height="80" src="https://en.mercopress.com/data/cache/noticias/110480/100x80/rj.jpg" style="float: left; margin: 0 12px 6px 0; border: 1px solid #333;" width="100" /> Two helicopters flying over Rio de Janeiro collided in mid-air on Sunday morning and crashed into an urban area of the city, in an accident that left six peopl...