Windsor Castle is a must-do day trip while visiting England. The 13-acre royal estate is about a half-hour train ride from London and then a short walk from Windsor Central Station. Your first glimpse is the western curtain wall constructed during the mid-13th century by King Henry III. This defense stands 100 feet and is 13 feet thick. On the left is Curfew Tower, a former medieval dungeon, built circa 1230. The belfry was originally part of the College of St. George and moved here in 1478. The clock was replaced in 1689. All of these features were restored in 1863. On the right is the Garter Tower. Its namesake is the knights of the Order of the Garter. Now hurry along. You haven’t come to the best parts yet.