The Taj Mahal was built by Shah Jahan in memory of his third wife named Mumtaz Mahal. Shah Jahan showed his father a talent in building right from the age of 16. His most reputable and grand achievement was building Taj Mahal. Here is a link you can refer to for more information http://en.wikipedia.org/wiki/Shah_Jahan#Taj_Mahal.
shah jahan got it built for the love of his life, mumtaz mahal, who was also his wife, after she passed away. it is also said that he cut all the workers hands after it was built because he did not want them to build anything more beautiful than this , ever again.