They are peeled, crushed, their juice extracted (the solid parts became cattle fodder), squeezed, boiled down, and the water evaporated until dry 'crystals' are left. The crystal form of the sugar is...
Sugar beets can be turned into invert sugar
Sugar beets can be turned into powdered sugar
Sugar beets can be turned into granulated sugar
Sugar beets can be turned into molasses
Growing Sugar Beets in Michigan
Sweet Beet Harvest - Part 2
Sweet Beet Harvest - Part 3
Families Who Produce Sweet Beets in Montana