Boro means 'temple', budur means 'mountain'?

Borobudur

This Buddhist temple was built in in the year 780 and covered in ashes from Mount Merapi (active volcano, approx 35 miles away) for about 1,100 years. In the 1800s, the temple was discovered by an Englishman, Sir Thomas Stamford Raffles,  and all ashes were cleared away by the Dutchman Cornelis Houtman a few years after. The mound that can be found close to the temple was formed by the cleared away ash. The building measures approximately 123 x 123 metres at its base, and is 9 stories tall. One can follow Buddha's life story through sculpted stones around the lower levels which are built in a rectangular fashion. The top level symbolizes 'Nirvana' and is round. No sculptures can be found there "since no one knows what Nirvana looks like. It is formless." A more accurate description can be found on Wikipedia, if you'd like to learn more.

Orange

There is no morter holding the 2.5 million stones together, and each of them have been numbered since the new foundation has been put in place. The faded orange that you see at times on the lower levels is remnant orange paint that was applied by the Dutch when they restored the temple the first time around (late 1800s).