Taj Mahal is India's national symbol of pride, not an enigma!!

Emperor Shah Jahan and Empress Mumtaz Mahal. Pinterest
Taj Mahal is, no doubt, one of the wonders of the world and tourists who have been to Delhi would never leave that place without seeing that magnificent marble  edifice  built by Shah Jahan in memory of his wife Mumtaz Mahal. It is a symbol of lasting love for his wife. This awe-inspiring mausoleum built on the banks of the river Yamuna carries an unsolved mystery and this "mystery element"  associated with a great monument of exceptional beauty makes us more curious than before to know something about the secrets. The mystery was kicked off by a historian one  Mr. P.N. Oak in the past.
actual tombs of Mumtaz Mahal and Shah Jahan - lower levelen.wikipedia.org
Inside the taj. Askideas.com
It is to be borne in mind that theories  and hypotheses over the Taj Mahal  being once a Hindu   heritage site have been set aside for decades and such discussions do not fall in the realm of  historical perspective.
It is the purported mystery surrounding the Taj that keeps our  mind occupied to get to know what are. According to Mr Oak Taj Mahal is a  Hindu temple dedicated to Lord Shiva named Tejo Mahalaya. How did Shah Jahan build the Taj in that place? Oak  suggested that Shah Jahan seized the Shiva temple palace from then Maharajah of Jaipur, Jai Singh. Once recovered,  Shah Jahan then redesigned and further embellished  the structure to suit his plan and converted it into a mausoleum - a memorial to his wife. 
In his 1989 book Taj Mahal: The True Story, revisionist historian PN Oak claimed the monument was built way back in 1155, decades before the Muslim invasion of India from NW. He  further mentioned that  its name is a corrupt form of the Sanskrit term “Tejo Mahalay”, meaning  a "Shiva Temple".

Many historians do not subscribe to his theory seriously because, in the past, he came up with incredible theories  such as Westminster Abbey was once a Shiva temple and Hindus once conquered Italy.  Such bizarre claims show him in bad light and lack of logic.

However, it is said that Shah Jahan admitted in  his own court chronicle, Badshah nama,  that an impressive beautiful  mansion in Agra was taken from Jai Singh for Mumtaz's burial. The ex-Maharajah of Jaipur is said to have retained in his secret collection of two orders from Shah Jahan for the surrender of the Taj building. Professor Marvin Miller of New York took samples from the riverside doorway of the Taj. Carbon dating tests revealed that the door was 300 years older than Shah Jahan and supports this theory.

Yet another theory is  European traveler Johan Albert Mandelslo, who on a visit to in 1638 (only seven years after Mumtaz's death),  gives a graphic account of the life of the town in his memoirs, but, surprisingly there is no mention of the Taj  that was in the making. Had the construction of the Taj  been going on, he would have mentioned it. His omission of the Taj  is a puzzle. 

 An English visitor to Agra within a year of Mumtaz's death, Peter Mundy,also suggest that the Taj was a noteworthy building long well before Shah Jahan's time.  That many rooms in the Taj Mahal have remained sealed since Shah Jahan's time, and are still inaccessible to the public adds new dimension  to the mystery. Oak Claims that the rooms contain a headless statue of Shiva and other objects commonly used for worship rituals in Hindu temples. Further, The Taj faces the East direction  and not West. The interior of Mumtaz's cenotaph contains figures of Sun and Cobra drawn in gold. Sun is redundant in Islamic structure. 

Taj. Controversial crescent symbol atop the dome. SlideShare
Mysterious Taj Mahal, Agra. YouTube 
In the recent past some BJP leaders resurrected some of the abandoned theories about Taj and its Hindu temple connection. The Pandora's box is closed tight and trying to break it open is not good. The Taj has been around us for a long time as symbol of India's  national pride  not only for Agra but also for the entire country. It surpasses caste, creed and religions. It is a great monument of grandeur and beauty, a sermon in marble that embodies the love between two souls who belong the Mogul dynasty.  English poet, Sir Edwin Arnold describes it as "Not a piece of architecture, as other buildings are, but the proud passion of an emperor's love wrought in living stones."