It's clear that Raul, co-owner (with his wife, whom I didn't meet) of this company, is doing what he loves: sharing the history of his beautiful city with others. He clearly cares both that his clients have a rich, educational experience and that they have nothing but good things to say about Rios de Historia.
Alas, our first tour, of the city center, was not so good. Perhaps our guide was having a bad day. Perhaps her English skills weren't quite there. I contacted Raul, explained to him the problems, and he responded quickly and professionally. He made time in his packed schedule to give my wife and me a private tour, taking us to Santa Marta, where we met a lovely woman who lives in the community and who showed us around. I don't doubt that my first, poor experience with Rios de Historia was an aberration and that, for those who seek more than a superficial tour of major sites, this is the company to contact.