This civilization is established as historic fact in India.
One of the most astonishing, of many, described in the Mahabharata and its astonishing component text the Bhagavad Gita, is a weapon too destructive ever to be invoked, viz. the Brahmashirastra.
BTW, the Bhagavad Gita is easily one of the most astonishing, valuable, and profound texts I have ever read. Its survival into the 21st century is a priceless miracle.
I have read it five times and struggled to read it in Sanskrit.
The phrase "I am become Death, the destroyer of worlds" is famously quoted by J. Robert Oppenheimer, upon witnessing the first nuclear explosion during the Trinity test. This quotation is from the Bhagavad Gita.
The Brahmashirastra (Sanskrit: ब्रह्मशिरास्त्र) is the most destructive weapon described in the ancient Indian texts. The Brahmashirastra causes chain reactions of massive explosions and waves to annihilate even the universe itself. Four people named in the ancient text possessed the knowledge of this weapon. This weapon can be invoked in any object, even to a blade of grass.
The Mahabharata names four people capable of understanding the Brahmashirastra. One was Arjuna, the hero of the Bhagavad Gita. He represents you and me and every one of us. Understanding this and the text can lead to astonishing insights.
We might add Albert Einstein as a fourth.
CORRECTION: As a fifth.