 Lists of unsolved problems

Lists of unsolved problems typically refer to compilations of questions or challenges that remain unanswered in various fields of study. These problems can span a wide range of disciplines, including mathematics, physics, computer science, biology, and philosophy. Below are some notable contexts in which lists of unsolved problems are often found: ### Mathematics - **Hilbert's Problems**: In 1900, mathematician David Hilbert presented a list of 23 unsolved problems.