It was built by the Mughal emperor Shah Jahan to house the tomb of his wife (and then later the emperor himself) and was built out of marble. The different colours on the building are purely a consequence of different varieties of marble from different parts of the world that have different colours. Artisans from all over were employed to do this work.

What’s also interesting, is that the minarets (the four tower structures) are tilted slightly outward to prevent them from crashing onto the dome in the event of an earthquake.

I’d seen pictures of Taj Mahal in the past, but I never really paid much attention to them – it was hard to tell that the building was built out of marble, so it just looked like a white structure to me. Upon seeing it in real life, I definitely had a much much greater appreciation for its beauty.

Links to photos here