I had a couple of days to spend in Johannesburg, so I decided to take a tour to learn something about South Africa as well as how diamonds are mined. I was lucky to get Marvin as a private guide for this tour. He was very knowledgeable and passionate about sharing South African culture with others. Marvin was also flexible and adapted the tour according to activity start times and my interests. At the Voortrekker monument I learned about history of the late 1800's and early 1900's. I knew very little about this before (other than hearing the name Kruger), so this was very interesting. At one of the lower levels there is a small art gallery which I thought was exceptional. Some works are for sale. I spent a fair amount of time touring the Kruger residence, where there was a lot of details about his life, especially his tenure as South African republic president. Being an engineer, my favorite part of the day may have been the tour of the diamond mine. I had a separate guide for this tour (I think her name was Sharon, but don't know the spelling). She taught me the geology of diamond formation, as well as techniques employed for recovering the diamonds. The tour includes walking outside and being able to see how the lifts and conveyors operate.