In 1687 Ottoman-controlled Athens, the Venetians blew up the Parthenon. The Ottomans built a mosque from its ruins.
The Parthenon, that most famous of Greek temples, has played a lot of roles in its nearly 2,500 year history. It has been a temple, of course, a treasury, and a Christian church. When Athens was conquered by the Ottoman Turks in the 15th century CE they converted it to a mosque, adding a minaret and a minbar (elevated pulpit)… but this mosque still used the original building.
All this time the Parthenon was completely intact, with a full supply of columns, a walled inner chamber, and a roof. It had been an imposing and secure building for millennia. In the 17th century CE, however, all that changed.
The Ottoman Empire and the Venetian Republic fought each other. A lot. Between 1463 and 1718 they had no less than seven wars – effectively spending one third of that whole period at war with each other. The sixth Ottoman-Venetian War came to Athens in 1687, and during a battle the Parthenon was used as a magazine for Ottoman gunpowder. It made sense, I suppose: it was a big secure building and its history and heritage should have dissuaded direct attacks.
Nevertheless, on September 26th a Venetian mortar hit the Parthenon and ignited the magazine. The resulting explosion disintegrated the inner walls, blew off the roof, and collapsed many of the building’s columns. The ornate marble decorations in and on the Parthenon fell; many were destroyed. What was left were a few still-standing columns and a whole heap of rubble.
The Venetians left Athens in 1688. The returning Ottomans took the rubble of the Parthenon and built a small mosque at its centre. The original building had been a mosque for a couple of hundred years at this point, so this was just a continuation of that use. The very first photo of the Parthenon, taken in 1839, actually includes the mosque:
Greece gained independence from the Ottoman Empire in the early 19th century, and the mosque was demolished pretty soon afterwards.