Within the main entrance is the Grand Staircase. This is a perfectly square room measuring 66.6 feet (20.3 m) on each side, which is meant to represent the numerological number 666, which are all the numbers added from one to 36, which is the square of 6, in mathematics, geometry, and arithmetic. The stair case is composed of three flights of steps each with 13 steps. The steps are brown-veined Carrara marble, the finest marble in the world. Flanking the steps are life size North American bison. Made of solid bronze, they were modelled by Georges Gardet, creator of the Golden Boy, and cast at the Roman Bronze Works in New York City. Each bison weighs 2,268 kilograms (2½ tons). Legend has it that to install the bison safely without damaging the marble floors, the main entrance was flooded and left to freeze. Both bison were then placed on enormous slabs of ice cut from the Assiniboine River, and safely slid into the building. The bison are one example of apotropaic icons in the Grand Staircase.
The bison, a symbol of the Province of Manitoba, are meant to represent the sacred bulls which guard temple entrances. Above the south entrance to the legislature lobby is the Medusa's head, and over the north entrance facing Medusa is the bust of Athena, Greek goddess of war, embodiment of democracy and also the protector of cities. Around the perimeter of the room are 14 lion heads and 8 cattle skulls at the edge of the ceiling. Around the second floor balcony, lamps rise from the balustrades, each containing 13 bulbs, 12 around 1 (Twelve Apostles and Jesus). The third floor facing the Grand Staircase is supported by two pairs of columns, reproductions of the caryatids, sculpted female figures serving as an architectural support taking the place of a column or a pillar. Each figure holds a scroll and key. The figures located on the third floor were sculpted by the Piccirilli Brothers of New York, using models prepared by Albert Hodge of London, England. The ceiling is made of a glass atrium to allow natural sunlight to illuminate the room.