The showed americans the vietnam war was not nearly over, as the government had suggested.

The correct answer is:  

Tet Offensive.  

The Tet Offensive (1968) by North Vietnam and the Viet Cong, was one of the most extensive military operations of the Vietnam War. It started on January 30, via units of the Viet Cong and North Vietnamese People's Army of Vietnam attacking the South Vietnamese Army of the Republic of Vietnam, the United States Armed Forces, and their allies.  

the triple alliance. germany and austria-hungary were already allies by 1879 when, worried about a threat from russia, they formed the dual alliance. italy joined the group in 1882. there was a concern about a possible attack from france and the alliance needed powerful friends to defend it.