The reference to the beauty of the number 153 can be found in the New Testament, where, in the net, Simon Peter drew from the Sea of Tiberias 153 fish. The number 153 has puzzled and intrigued Christian thinkers for centuries. Pythagoreans regarded 153 as a sacred number due to its use in a mathematical ratio called the measure of the fish. Interesting coincidences include the mention of 153 in The Ascent of Rum Doodle, a novel by W. E. Bowman. Mathematically, when the cubes of the digits of any number, that is, a multiple of 3, are added and then this process is repeated, the final result is always 153, where the process ends because 153 = 13 + 53 + 33. The number 153 is the only known smallest number in a set of three consecutive triangular numbers with three prime factors, which is not square-free. Such unusual mathematical curiosities, along with amazing coincidences, are illustrated in this chapter.