The Pink Tower is the iconic Montessori material. Often called the symbol of Montessori, it is a recognizable sign in all Montessori environments. Part of the sensorial area, it is made of ten pink wooden cubes, in three different dimensions. The smallest of the cubes is 1cm (3/8"in) cubed, and the largest is 10cm (4"in) cubed. The cubes progressively get bigger in the algebraic series of the third power. This means the second cube equals eight of the first (23), the third cube equals twenty-seven of the first (33) and so on.

The purpose of this series of cubes is to develop visual discrimination of size in three dimensions. Exploration with this material prepares the child for mathematical concepts in the decimal system, geometry, and volume.