St. Stephen's Cathedral

Look up at that soaring south tower. The Viennese call it Steffl, an affectionate nickname for Stephen. It took 65 years to build, from 1368 to 1433, and at 136 meters tall, it dominated Europe's skyline for decades.

See the north tower on the other side? It's only half as high. Construction stopped abruptly in 1511. Not because they ran out of money or ambition. The Ottoman Turks were advancing on the city, and every stone and worker was diverted to strengthening the city walls instead. The last batch of stones installed still bears the year 1511.

That roof you're admiring has 230,000 glazed tiles forming a Habsburg double headed eagle in black against diamond patterns. Each tile weighs 2.5 kilograms. The roof is so steep it cleans itself when it rains.

In the north tower hangs the Pummerin, Austria's largest bell at 20,130 kilograms. It was cast from Turkish cannons captured during the 1683 siege. Beethoven realized the full extent of his deafness here. He watched birds scatter from the bell tower, their flight caused by bells he could no longer hear.

You're standing on ground that's been sacred for nearly 2,000 years. Excavations in 2000 found graves from the 4th century beneath your feet.