Enjoy a leisurely walk around a former landfill that has been converted into a coastal pond that attracts hundreds of species of birds. You will find Centro Habitat Mediterraneo near the mouth of the Tiber River in the Ostia neighborhood of Rome. A dump site there was supposed to be developed as an oceanarium, but the residents of Ostia voted to turn it into a nature reserve instead. The transformation has been a success from the beginning. The reserve now features an informative nature center and a winding walkway, viewing platforms and a lookout tower for bird-watching. Kingfishers, marsh harriers, flamingos, purple herons and little grebes are the five most commonly spotted birds. But there are plenty of others, including European bee-eaters, black redstarts and chiffchaffs, an olive-brown warbler named for its distinct repetitive song. During free time in Ostia, you may also catch sight of Tor San Michele, a fortified tower that Michelangelo designed in the 16th century.