I live in the Houston area and I have NEVER done this tour! Luis was such a knowledgeable tour guide. He was friendly and welcomed our many questions without making us feel silly for not knowing something. As a matter of fact, he ENCOURAGED our questions! Luis did not rush us on the tour and stayed as long as we wanted to in order to cover so much territory. It is well worth the +/- $25 for the tour - even if you equipped yourself with a map of the tunnel, it would be difficult to decide on which buildings to to in to, and you certainly would not know of the history of so many of these beautiful buildings. My stepmother, a frequent visitor to Houston, told me that this is one of the most interesting things that she has EVER done in Houston!