The picturesque Old Town of Valencia remains the heart of the city, and within this ancient district El Carmen is the city's favourite 'chill out' zone, with its narrow alleyways, honey-coloured buildings, Bohemian atmosphere and nooks and crannies packed with bars and cafes. Apart from being the ideal spot for people-watching, El Carmen also has several interesting attractions, including the remains of the medieval city walls, the Gothic towered gates of Torres de Serrano and Torres de Quart, the latter pocked with cannon-ball marks dating from an assault by Napoleon. Also in El Carmen is a convent complex dating from the 13th century, and several museums. Roman and Moorish influences are clear in the Old Town of Valencia and the numerous squares and narrow streets give the area an authentic medieval atmosphere despite the invasion of tourists as the city increases in popularity. El Carmen is the best place to enjoy the cafes, bars and restaurants that spill out onto the cobbled streets and bustle until the early hours of the morning. The Cathedral of Our Lady is a good starting point for a walking tour of the Old Town, and climbing the cathedral's tallest tower will earn travellers fantastic views. Mercado Central, one of the largest indoor markets in Spain, is also quite an experience.