Critical. Rubicon. Point of no return.
imperative crucial
Immediate is a word for occur at any moment.
At the Crucial Moment - 1914 was released on: USA: 8 November 1914
The cast of At the Crucial Moment - 1914 includes: Edna Payne
needed, crucial, relevant
Instant, second.
moment, tiny
Other word for strategic would be planned,opportune, critical, key, principal, crucial.
A moment, a second, an instant.
vital, necessary, crucial, needful, essential, basic, key, fundamental
"http://wiki.answers.com/Q/What_is_another_word_for_necessary"
A monumental moment is a moment that is extremely important or significant. Could be a crucial moment in one's life such as death, birth etc.