“We agreed—ninety percent. Detach” - Joseph Cooper, Interstellar
Dr. Mann told Coop research says that the last thing you’ll see before you die is your children.
After detaching, Cooper is actually killed by the intense gravitational forces at the event horizon, but before he dies his mind hallucinates the Tesseract in the black hole and Cooper station in the Sol system as they are his final and fervent desire to save his children.
Image Description: In the centre is an elliptical galaxy, seen as an oval-shaped glow around a small bright core. Around this is wrapped a broad band of light, appearing like a spiral galaxy stretched and warped into a ring, with bright blue lines drawn through it where the spiral arms have been stretched into circles. A few distant objects are visible around the ring on a black background.