Question

During the Tet Offensive, the NLF and North Vietnamese what?

Answer 1

They launched a massive surprise offensive in South Vietnam, simultaneously attacking around a hundred towns and cities throughout the country.

It was called the Tet Offensive because of the attack took place during the Tet lunar year celebrations. A two-day cease fire was announced by both North and South Vietnam previously, so the attack came as a surprise both for the blatant disregard for the cease fire and the incredible size of the offensive action.