The Tower of London was built upon command of William the Conqueror in 1078. It was never completed in his lifetime and work continued under the watch of William II. The first sections of the tower to be completed were the White Tower and the Norman Church- which remains the oldest church in London today. Between the 11th and the 15th Century the Garrison was rebuilt and enlarged. The inner wall was constructed by order of King Henry VII and Edward I built Traitors Gate and the St. Thomas Tower. Located on the North bank of the River Thames- the Tower of London strikes a formidable presence over modern London. Now the home of the Crown Jewels, the Tower of London has had a varied and macabre past. Over the last ten centuries the tower has been a palace, a prison an arsenal and even a zoo. Free tours are run by the Yeoman Warders and among the exhibitions is an insight into the creation of Royal crowns, located in the Martin tower. The considerable dry moat that surrounds the tower is more than a kilometre in circumference and was created as a defence mechanism. Tower Bridge Underground station gives excellent access to the site from the city centre.