Different people have different views of the Taj but it would be enough to say that the Taj has a life of its own that leaps out of marble, provided you understand that it is a monument of love. This is a tribute to a beautiful lady 'Mumtaz Mahal'.
When Mumtaz Mahal was still alive, she extracted four promises from the emperor 'Shah Jahan':
[1] He build the Taj.
[2] He should marry again.
[3] He be kind to their children.
[4] He visit the tomb on her death anniversary.
To keep his promise, he built this beautiful monument.