The Winter Chapel was dedicated to the Blessed Virgin, the windows represent her own symbols:

The Rose; The Passion Flower; Pomegranate; Crescent Moon, Fleur-de-lis; Lily; Palm and monogram

“When we build, let us think that we build forever.  Let it not be for present delight nor for present use alone.  Let it be such work as our descendants will thank us for, and let us think, as we lay stone on stone, that a time is to come when those stones will be held sacred because our hands have touched them, and that men will say as they look upon the labor and wrought substance of them.  See!  This our father did for us.”

John Ruskin

Celestial Windows on the Gospel (Left) side are the Twelve Apostles (pictured St. Peter)

Ambulatory Windows (those you can walk by) are the emblems of the patron saints of different countries (pictured St. Joseph-Belgium)

Celestial Windows on the Epistle (Right) side are the Great Doctors of the Western Church (pictured St. Ambrose)

The Bapistry is located at the north end of the narthex (entrance hall).

The picture is of Our Lady of Perpetual Health

The Rose Window is located above the choir loft and organ. The circular shape signifies God's infinite nature, perfection, heavenly realms and endless love.