Take a ride into the past. Next stop... ancient Greece

Athens's new metro is like an underground museum: the line weaves through the old city, dodging archaeological finds along the way.

Think of modern Athens and you'll probably picture a sweltering, polluted and traffic-ridden metropolis, where renowned antiquities such as the Acropolis are best visited either out of season or very rapidly before heading for the islands. There's undoubtedly an element of truth in this and yet, as Athens begins its annual drama and music festival, getting round the city has got a little easier (and hopefully less polluted) thanks to some new metro lines.

Think of modern Athens and you'll probably picture a sweltering, polluted and traffic-ridden metropolis, where renowned antiquities such as the Acropolis are best visited either out of season or very rapidly before heading for the islands. There's undoubtedly an element of truth in this and yet, as Athens begins its annual drama and music festival, getting round the city has got a little easier (and hopefully less polluted) thanks to some new metro lines.

In other capitals delays to new public transport facilities are usually caused by political in-fighting or squabbles over finance. In Athens the construction of two additional metro lines, which was originally planned for 1998, was held up by one archaeological discovery after another. The results are stunning. With their sparkling clean carriages, billboard-free walls and orthopaedically designed seats, the two new lines are a stark contrast to the very unglamorous original green line, and the city is now graced with beautiful and innovative metro stations that combine history lessons and modern design - and also mean that travellers can flit between sights in air-conditioned comfort.

The centrally-located Syntagma (Constitution) Square station is an essential stop for anyone wanting to get a feel for the day-to-day bustle of Athenian life, watch the changing of the guard outside the Parliament Building or retreat from it all in the National Gardens or the elegant café of the Grande Bretagne Hotel. Over a thousand graves were discovered during excavation work beneath this bustling crossroads, and the station is now a showcase for several dozen artefacts.

Busy commuters can snatch a quick glance at their city's past while more leisurely travellers can stop and imagine what was once lit by 4th-century BC clay lamps or admire the details of a 4th-century mosaic. Instead of advertising, passengers emerging from train level are confronted with a large picture of the historic Messogiaki gate through which their predecessors once entered the city.

Further along the blue line, near the Evangelismos station, more artefacts were unearthed. Along with copper mirrors and religious and secular statues, a section of the city's Roman era aqueduct system was found and has been incorporated into the station. Hop out here and find out more about the area's past by visiting the lovely Byzantine Museum.

Old and new intersect at the busy Monastiraki stop: the narrow streets have always been at the heart of Athenian life, and the area retains some authenticity in spite of the tourists. The locals queue up outside the station to buy pistachio nuts on the way to work, and old men play backgammon at street-side cafés, oblivious to everything but the next move.

But don't stop your underground tour here. As it wormed its way under the city, the giant "Metromouse" unearthed baths at Amalias Avenue, workshops and an ancient road near the site of the current Evangelismos Hospital, and yet more graves near Kerameikos, many of their lamps, toys, religious statues and beautification pots still in astonishingly good condition.

The most precious findings the new line uncovered include the intact grave of a somewhat pampered hunting dog showered with burial gifts. To see these you have to carry on to the Museum of Cycladic Art (4 Neophytou Street, Evangelismos station). Here a new exhibition displays those artefacts considered just too important for everyday metro stations.