Cincinnati Mercantile Library

In 1845, the Mercantile Library burned down. But as a result the members struck a real-estate deal that would last for millennia.

Founded in 1835, by a group of Cincinnati merchants, the library quickly became an intellectual center for the city. Members paid dues and pooled their books, and as the institution grew it became a venue for some of the most celebrated speakers and writers of the age. 

In 1840, the library moved its small collection, of about 700 books, into the building of Cincinnati College. Five years later, the building caught fire and burned down. The members of the library raised $10,000 to help rebuild. In exchange for those funds, the college offered the group a lease that would last 10,000 years—one year for every dollar donated.

For the 1840s, $10,000 was a large sum of money, worth hundreds of thousands of dollars today. But it was still an excellent deal for the library. And, one of the most advantageous terms of this lease is that it's renewable, for another 10,000 years. 

Today, the library has tens of thousands of volumes and takes up two floors of a building in downtown Cincinnati. Its wood-paneled rooms still host lectures from luminaries, and the library still has around 2,500 members, who pay annual dues of $65.