The Taj Mahal was built by Emperor Shah Jahan, in the memory of his third wife, Mumtaz Mahal, who died during the birth of their fourteenth child. It was built in the period 1632 to 1653, and involved thousands of craftsmen, artisans, and laborers.
The Taj Mahal is located in Agra and has been a UNESCO World Heritage Site for about 25 years. It has been identified as "the jewel of Muslim art in India and one of the universally admired masterpieces of the world's heritage."
One way to see the Taj Mahal would be as part of an Indian Tour Package. There are a range of packages from inexpensive to upscale ones like Tauck Tours.
If you are on your own and anyplace near Agra in India (and it could be worth a dedicated sightseeing trip) you must visit Taj Mahal. There are dozens of local tour options to see the Taj Mahal from New Delhi (a distance of about 120 miles away). Some of the tours involve a guide meeting you at your hotel and escorting you on the train to Agra, others involve group buses, there are flights from Delhi to Agra, and others involve taxis or minibuses. The tours that are booked through your hotel desk are probably the most expensive, but possibly also the most reliable.
I was taken by private minivan with another tourist. We left early in the morning, and the drive (like all driving in India was very exciting). There is no way that I would ever consider renting a car and driving myself in India. There are a variety of hotels and other accommodations should you desire to spend the night in Agra (which might make the visit more relaxing).
It was interesting that the entrance fees for foreigners were an order of magnitude higher than those for Indians, however foreigners received a bottle of water and could use the toilets without additional fees. The fees were reasonable for a world historical site and I am not complaining.
The scale, quality, uniqueness, and whole atmosphere make the Taj Mahal a very special and romantic place. See the Taj Mahal while you can, there are occasional rumors that it will be closed to tourists to minimize the impact of pollution and visitors.
If you are going to visit the Taj Mahal, you might consider reading the historical fiction novel "Taj" by Colin De Silva.