The base 10 system, also known as the decimal system, is unique because it is the most widely used number system in the world and has been adopted by nearly all cultures and civilizations. The reason for this widespread usage is that it is based on the number of human fingers, with 10 being the number of digits on two hands. This made it a convenient and intuitive system for early humans to count and perform mathematical operations with. Additionally, the base 10 system allows for easy representation of numbers using only 10 symbols (0 to 9), making it simple to write, communicate, and perform mathematical operations with larger numbers.