Strasbourg's historic old town is dominated by the spectacular Notre Dame Cathedral, with its famous astronomical clock. The Cathedral has remained unchanged since the Middle Ages. Around the Cathedral clusters an impressive array of museums, cafes and restaurants. The Grande Ile (Large Island) - a UNESCO World Heritage Site - in the midst of the River Ill, is the ancient heart of the city, with the vast main square, Place Kléber, at its centre. Close by is Place Gutenberg - named after 15th-century Strasbourg resident Johannes Gutenberg, famed for his development of printing.