located on the eastern side of the city, guanabara bay is opened by the pão de açúcar mountain, at its western tip, and goes on to stretch an impressive 31 kilometers long and 28 kilometers wide.

with a surface area of nearly 400 square kilometers, the bay has a 130 km perimeter and measures between 28 to 30 km form sides to sides, with the entrance into bay facing the ocean and 1700 meters wide.

the bay formed at the end of the last ice age, when the ice sheet melted and left water in its place, causing the bottom of the bay to be muddy, as it remains to this day.