The enormous barrel vault and igloo vault ceiling makes it feel as though the building soars into the heavens - especially with the celestial mural painted across it. This is probably the most famous ceiling today.

The ceiling of the Main Concourse at Grand Central Terminal features a world-famous celestial mural depicting the Mediterranean sky during the October-to-March zodiac. Painted by French artist Paul Helleu and Charles Basing, the mural includes 2,500 stars—59 of which are illuminated by LEDs—and gold-leaf outlines of the twelve constellations of the zodiac. A "High-Fidelity" historical quirk of the ceiling is that it was actually painted backwards; the constellations are shown as if viewed from "God's perspective" above the stars, rather than from Earth. Another famous detail is a small, dark "soot patch" near the constellation Cancer, which was intentionally left uncleaned during the 1998 restoration to show how much grime and nicotine had accumulated on the ceiling from decades of indoor smoking. The mural serves as a majestic canopy for the roughly 750,000 people who pass through the terminal daily, reminding travelers of the ancient link between navigation and the stars before the era of modern rail and GPS.