Two giant towers of light have lit up the lower Manhattan skyline as a visual memorial to those who lost their lives on 9/11.

The September 11 Memorial & Museum's "Tribute in Light" art installation switched on just after sundown Monday.

The light beams reach up to four miles into the sky and are comprised of 88 searchlights positioned into two squares that represent the twin towers.

The Memorial Plaza will be open to the public until midnight Monday to view the lights, which were first installed six months after the attack and are now a yearly tradition.

They'll stay lit until dawn.