In 1974, the architect and professor Ernö Rubik attempted to build a contraption that would demonstrate 3D movement to his architecture students. He eventually did so successfully, but he later realized that his novel creation was much more than a demonstrative tool.
Soon, he scrambled his contraption, and reportedly spent around a month trying to restore the cube to its original configuration. Afterwards, he applied for a patent for his "Magic Cube" in 1975, which was approved.
Further reading: The Perplexing Life of Erno Rubik.
The normal 3×3×3 Rubik's Cube has a total of 43 quintillion configurations, or 4.3×10¹⁹ total configurations. It has a total of 26 smaller 1×1×1 cubes, with the remaining 1×1×1 portion being the core in the middle that helps holds the cube together.
The 3×3×3 can make 90° turns on all faces. It has a total of six sides; white on the top, red to the sides, then blue to the right of red, orange to the right of blue, green to the right of orange (and to the left of red), and yellow on the bottom.
There are more Rubik's Cube variations that have been made over time, and each present their own set of unique challenges. Examples of variations are other N×N×N puzzles like the Rubik's Revenge (the 4×4×4 version) and the Professor's Cube (the 5×5×5 version), shape mods such as the Megaminx, and the and cuboids such as the 2×2×N Tower Cuboid series.
Here is a helpful guide from the official Rubik's brand on the beginner's method on how to solve the Rubik's Cube.
The World Cubing Association, or the WCA for short, is an organization that hosts Rubik's Cube competitions around the world. It features speedsolving events for multiple puzzles, such as solving the 2×2×2 to 7×7×7 puzzles, solving several Rubik's Cube shape mods, and many others.
CFOP, whose letters stand for each of the four steps used in this solving method, is a popular speedsolving method that has been used by world record holders. There are 119 algorithms in total, each of which focus on specific cases for each step.