I've noticed that in Spanish, when using an exclamation mark at the end of a sentence, we also need an upside down one at the beginning. The same is the case with question marks.
For example: ¡Adiós! - ¡Hasta luego! - ¡Chao! ¿Cómo te llamas?
1) What is the reason or explanation for this doubling?
2) What is the reason for putting the beginning matk an upside down?