Ever since a digger clattered into a buried wall seven years ago, experts have been intrigued and perplexed by Swindon's mysterious Roman complex. But yesterday, English Heritage revealed that the enigmatic site in the heart of a housing estate was once a magnificent, luxurious villa.Today and tomorrow, members of the public have their only chance to view the historic find before the site is buried once again.English Heritage was overjoyed at uncovering the well-preserved remains of a spacious Turkish bath-like complex after a seven-week dig at Groundwell Ridge. Experts said the elaborate Roman baths and heating system, dating back nearly 1,900 years, exceeded their highest expectations.The excavation area comprises about 20 per cent of the villa which was occupied by wealthy, powerful Romans over 250 to 300 years from the second century AD.English Heritage's chief archaeologist David Miles said: "The villa would have had running water, lavatories, baths, a gymnasium, rooms with plastered walls, window glass and a central-heating system."No one in Britain would live in this sort of luxury and comfort until the late 18th and early 19th century."It may have been occupied by two or three arms of a family of perhaps 20 people, surrounded by scores of servants, slaves and peasants.Mr Miles said the villa - the centre of a thriving estate - had been enlarged, improved and redeveloped around five or six times over three centuries. The baths, and hopefully the rest of the villa, are so well preserved because the site, being on a slope, was not heavily ploughed.As well as the clearly identifiable remains of tiled bathing areas, archaeologists discovered a tiny lead plaque of Minerva, the Roman goddess of wisdom.Such was the villa's importance, English Heritage stumped up its largest-ever grant, £854,000, to help buy the 12-acre site from developers, while Swindon Council forked out £100,000.