Only somewhat altered from the original configuration
(1898-1902), the Great Hall is described as R.M. Hunt's
'most ambitious' Beaux-Arts design. Replacing the south
facade of Weston's addition as the main entrance to the museum,
the three-domed, stoically Classical scheme rationally organizes
the museum patron's first impressions of the building. Like the
crossing of a church, the central dome marks the intersection of
the Great Stair, which leads up to the painting galleries in the
old building, and introduces the galleries to the north and south.
The McKim, Mead and White additions enlarged these end galleries
into large wings which today house Greek and Egyptian art.

The Hall is a space which is conducive to just being in. There is no art
displayed in the Hall; it serves as the gateway to the rest of the building.
The feeling is one of being surrounded on all sides with high Culture; the
Beaux-Arts architecture offers the "best" building that Western culture can
offer. This is most sublimely illustrated on Friday nights, when the lights
are low and the chamber music floats from the balcony above.

from: http://www.jdwelch.net/writing/metarch.html