LONDON.- For over 800 years, Windsor Castle’s world-famous Round Tower has dominated the surrounding landscape. Now a new guided tour, ‘Conquer the Tower’, takes visitors inside the Round Tower and up 200 steps to the top of one of the nation’s iconic landmarks. From a height of 65.5 metres above the River Thames, they can enjoy breathtaking views of the Castle and historic parkland, the Thames Valley, the London skyline and across several counties. The tour runs daily throughout August and September 2011. Windsor Castle was first established by William the Conqueror in 1070-86 as one of a chain of fortifications around London, securing the western approach to the capital. At the heart of the Castle was an artificial mound (motte) formed by chalk spoil from the surrounding ditch and topped by a wooden keep. In 1170, Henry II replaced the Norman keep with the Round Tower, built with heath stone from nearby Bagshot. The appearance of the Round Tower today dates from George I