For hundreds of years the Roman theatre at Bosra, southern Syria, was literally buried in the sands of time.
It took more than 20 years to clear out the sand to reveal what is considered the most perfectly preserved Roman theatre in the world. It was not only the sand that helped keep this 2nd Century AD building intact but the fact that during the 13th century it was incorporated into an Arab fortress.
Today Bosra feels rather out on a limb, lying as it does east of the main highway linking the Syrian capital of Damascus with Amman, the capital of Jordan and only a few kilometres from the border between the two nations. But it was not always a quiet backwater.
About 2000 years ago the Nabateans, who created legendary Petra to the south, made Bosra the capital of their kingdom. Even earlier the Egyptians had known about Bosra as had Seleucus, one of Alexander the Great's generals.
When the Romans arrived, they too realised its strategic importance and declared it the capital of Provincia Arabia. Bosra thrived, placed as it was on a trading route that stretched from the Red Sea into the heart of Mesopotamia.
It was during this time that the vast theatre, an essential element of a prestigious Roman city was built.
Later. the Byzantines came to Bosra, building one of the largest cathedrals in the Middle East. It is believed that a young man on a trading journey visited it and discussed religion with one of the priests. He was later to become the Prophet Mohammad.
During the Middle Ages the Crusader armies attacked the town several times, which was the impetus for the local Arabs to encase the theatre in a fortress.
They did such a good job that when early 19th century European travellers visited the town they had no idea a theatre lay inside the fortifications. And as the area's importance began to decline further the theatre itself continued to fill up with sand. Excavations only began in the late 1940s.
Today travellers often visit Bosra as a day trip from Damascus but my three visits have always been en route to cross the border into Jordan.
It's easy to see, as one walks up to the main entrance why the theatre stayed under the radar for so long. With a moat, fortified walls and massive gateway it gives away nothing of the Roman structure that lies within.
What also makes the entire complex extraordinary is that it is built of local black basalt, which gives it a rather forbidding and appropriately military air.
Even when one enters through the fortress gates, Bosra's secret remains intact. There's the usual zigzag passageway designed to disorient and slow down attackers and then vast stone-flagged corridors lead off left and right into the gloom.
If you opt to take the stone stairs up several levels the shadowy interior suddenly gives way to a sunlit narrow terrace and a row of arched doorways. When one steps through one of these the glory of the theatre is revealed.
Serried ranks of seats in 37 rows sweep down towards the stage which is backed by lofty Corinthian columns and a facade decorated with carvings.
There are seats for 15,000 spectators with room for a further 3000 people to stand. Historians estimate that during important festivals, about 30,000 people could be crammed in.
Even in early spring the theatre warms up fast and the sunlight is blinding. But during Roman times spectators would have been protected by silk awnings and actors on the stage would have had a wooden roof overhead. It's also thought that perfumed water was sprayed over the audience to further refresh them.
The view is equally dramatic from stage level with the seats rising up towards the skyline and the silhouetted pillars. The acoustics are perfect - an actor could speak at normal volume and be heard in the back row.
To the left and right of the stage are tall arched doorways, known picturesquely as vomitoria. While it's tempting to imagine this as a sanctuary for hungover theatre patrons or maybe distressed critics, the name actually relates to the surge of people passing through them to and from their seats.
People-watching is fascinating here. The extroverts and would-be actors love the stage - they sing or recite, sometimes to an appreciative audience of two or three friends, or even to ranks of empty seats.
Other visitors prefer to sit high in the theatre itself, their backs against the warm basalt just as Roman audiences did 2000 years ago. From here one can watch the passing parade on stage - Syrian children darting out of the stage doorways, Italians singing opera, English amateur historians in earnest huddles and even Kiwis working out who knows all the words to Pokarekare Ana.