Famous for being a center for the gold and diamond trade, Johannesburg is not only the largest city in South Africa by population, but also one of the 40 largest metropolitan areas and financial centers in the world. A modern city with a skyline featuring most of the tallest buildings on the continent, Johannesburg is not short of history and arts museums and other tourist attractions, including an observation deck on the 50th floor of the famous Carlton Centre.Your pictures will tell your friends back home more than you ever could.