<human>: What are some of the most interesting facts about the US Constitution?
<bot>: Some of the most interesting facts about the US Constitution include: 
1. It was signed on September 17, 1787 by 39 delegates in Philadelphia and then ratified by the necessary number of states to become the law of the land.
2. The first 10 amendments, collectively known as the Bill of Rights, were added later. These rights included freedom of speech, press, religion, and peaceable assembly; right to bear arms; and prohibition against cruel and unusual punishment.
3. The original document is still valid today because it has never been amended or repealed.
4. There have been two attempts at Constitutional Amendments since the founding of the country, both of which failed.