Turkey is a paradise for lovers of Greco-Roman history. In fact, it's been said that there are more Greek and Roman ruins in Turkey than there are in Greece or Italy. We managed to see quite a few during our travels around western and central Turkey.

Ephesus
Even though only about 20% of this massive ancient city has been excavated, it's the most complete classical city in Europe. If you have to pick just one classical ruin to visit, make it this one. Founded by the Greeks in the 4th century BC, it was taken over by the Romans a couple of hundred years later.
Wandering around the site, we saw the crumbling remains of temples, typical homes, communal baths, a huge amphitheatre, and even public toilets. A wide, sloping street that has been repaved with new stones leads down to the most impressive structure, the two-story facade of the Library of Celsus. At one point, over 12,000 scrolls were stored there. The site is a big draw for tourists, so be prepared to share it with thousands of other visitors.

Our base for visiting Ephesus was the town of Selçuk, right next door. While we were in the area, we paid a visit to the ruins of the church of St. John on the edge of town, reached by a short uphill hike.
The church was built by Christians in the 5th Century AD on the site believed to be the final resting place of John the Baptist. Its 6-domed structure must have been impressive when it was brand new, dominating the hilltop so as to be seen for miles around.
Today, pillars and archways form a partial outline of the church, and carved marble slabs are scattered around the site along with broken blocks and bricks. Wildflowers grow between the cracks. The combination of red brick and white marble is striking.

Pergamum
This city dates back much farther than Ephesus - all the way back to the 12th century BC. This is the ruin to choose if you prefer some semblance of solitude. We practically had the place to ourselves when visiting on a weekday in May. Our guide drove us in between some of the farther flung monuments, since they were spread out over six kilometres.
The views from the hilltop acropolis were expansive, giving an overview of the ancient city and the modern town of Bergama butting up against it. We enjoyed even more impressive vistas from the hillside amphitheatre, the steepest in the ancient world.
One of the most interesting buildings is the Asklepion, or medical centre. This was the birthplace of the Hippocratic Oath still taken by medical professionals today. It was also a top clinic for Roman emperors to visit when seeking the finest medical care in the Empire. Sort of like a Mayo Clinic of its time, I suppose?

Priene, Miletus & Didyma
We saw this trio of ancient Greek cities in Southwest Turkey in a single day trip, since they're within 40 minutes driving of each other.
Priene was established in the 14th century BC, making it the oldest classical city I've visited. In its peaceful, sheltered location, the Temple of Athena is the main attraction. Five of the original 66 columns still stand, with pieces of the other 61 scattered around the site. Of course, the obligatory theatre is there, and in this case it's well-preserved. Five large stone armchairs with lion-paw armrests are a unique feature.

Miletus was one of the first cities to produce coins, and it was mentioned in Homer's Iliad. It once had three harbours, but they'v silted up so much over the centuries that the coast is now eight kilometres away. My favourite part of this site was the Baths of Faustina and its Hall of Muses with niches that once held statues of gods and goddesses.
Didyma was busier than the other two sites - its Temple of Apollo seems to attract the crowds. Historically the city was connected to its twin city of Miletus by way of a long paved road. It was a sacred route that allowed pilgrims to travel between Didyma's Apollo temple and the Athena temple in Miletus. Didyma's other notable monument is an awesome huge gargoyle of Medusa's head. Thankfully I did not turn to stone after looking at it.

Hierapolis
A couple hundred kilometres east, on a hilltop overlooking the famous Pamukaale travertines, sits the ancient spa town of Hierapolis. Together, these two sites are well worth a visit.
One the most unique features of Hierapolis is called the Martyrium of St. Peter the Apostle. It's an octagonal structure made up of eight small chapels. Popular belief is that Peter was killed here after chastising the local pagan snake worshipers a little too harshly for their liking.
A few years ago, remains believed to be those of St. Peter were found only 40 metres away from the Martyrium. It's believed that he was crucified upside down at his own request, since he felt he didn't deserve to be crucified the same way as Jesus. Some Catholics still use the inverted cross to represent St. Peter and his humility.
Just outside the ancient city walls, another haunting site is the necropolis, a collection of tombs, graves and sarcophagi, some elevated on stone stilts. Many are engraved with Greek letters and symbols. The site has been left to nature -- unmarked and unkempt, with the burial structures partially taken over by tall grass and weeds. It seems fitting; a more natural and contemplative experience that preserves the dignity of those who rest there.

Getting to the ruins
The town of Selçuk is a convenient base for seeing a number of these ruins. We stayed there for a few days and took a couple of day trips. Ephesus was a short taxi ride and Pergamum was a long day trip (two hours driving each way). Many local operators combine Priene, Miletus and Didyma into a single day trip, which is exactly what we did.
Hierapolis and Pammukale are about three hours away from Selcuk. It's worth spending a night or two in that area to see both the ancient city and the travertines. There is a well-developed tourism infrastructure in Pammukale, including many hotels and good transportation links.

The most convenient way to travel distances by land in Turkey is the extensive network of inter-city buses. The modern coaches are quite comfortable and ticket prices are affordable. During our journeys, we were treated to refreshing lemon water to wash our hands, hot tea, cold drinks and snacks. There are a few companies to choose from; my favourite, at least in name: Kamil Koc (aka Camel Coach).