The Taj Mahal was built by Mughal Emperor Shah Jahan in memory of his wife Mumtaz Mahal. The construction began in 1623 AD and was completed in 1648 AD. It is considered to be the greatest architectural achievement in Indo-Islamic architecture, as it sits upon the right bank of the Yamuna River in the Agra District in Uttar Pradesh. The building was made from brick-in-lime mortar veneered with red sandstone and marble and inlay work of beautiful stones. The Taj Mahal contains many remarkable features, such as the placing of a tomb at one end of the garden rather than in the exact center. The most impressive feature, however is the way the Taj Mahal is a perfectly symmetrical planned building.
Here is a link from UNESCO World Heritage Centre: