Simplify the following text for a Grade 8 native English-speaking person.
Original: Reliant Astrodome , also known as the Houston Astrodome or simply the Astrodome , is the world 's first domed sports stadium , located in Houston , Texas , USA .
Simplified: The Reliant Astrodome , which was called `` the Astrodome '' , is a domed sports stadium . The Astrodome was the first of its type built .