A significant increase in the number of second homes is threatening the beauty of Tuscany, according to Italian environmentalists. Modern villas and flats are springing up near medieval towns or blighting valleys once covered by olive groves, says the pressure group Legambiente. It says the region's beauty is under assault from "rivers of cement". Eduardo Zanchini, a spokesman for the pressure group, said: "Second homes are not the future of Tuscany. If we don't limit this construction, Tuscany will become like the other areas of Italy that have been ruined by overdevelopment. We need to cherish this landscape." Concern about a building boom in Tuscany was brought into focus by Alberto Asor Rosa, a professor at La Sapienza University in Rome, who warned that some of Tuscany's most beautiful areas, such as the Val d'Orcia, were being exploited. His complaints have covered projects such as new flats near the historic hamlet of Montichiello, near Pienza. The apartments were meant for local people but the project was enlarged to 90 units, housing an estimated 300. The project is being advertised in Rome papers as offering a chance to buy second homes. The project is now under the scrutiny of Italy's culture minister, Francesco Rutelli. Other unwelcome construction projects have been identified at Grassina, where homes are going up in front of the town's ancient walls. At Massa, magistrates opened an inquiry into the construction of nine hotels split into mini-apartments and sold off as second homes. At San Vincenzo, on the Tuscan coast, there are plans for a mega-hotel and luxury flats on 540 hectares (1,335 acres). Legambiente says it is renewing the effort to slow the boom. "Developers are going to mayors and saying 'we will give you this money that you can spend on improving local services if you let us build here'," Mr Zanchini said.