Why is the Taj Mahal/Great Wall/Pisa Tower not on the list?
The original list was compiled by ancient Greek historians before the Taj Mahal or the Pisa Tower were built. These historians did not know of the existence of the Great Wall (which did not take its present shape until the Middle Ages anyway). When the Dutch architect Maerten van Heemskerck compiled the final list in the Middle Ages, he relied mostly on the ancient Greek sources. In this WWW site, we have devoted a complete section to some of the greatest Forgotten Wonders.
