Few cities have so many places of interest concentrated into such a small area as the Scottish capital. The availability of flights from other UK, and most European, airports make it a popular destination for weekend breaks and longer visits. The easiest way to find a cheap flight from London Southend, for example, is to use a flight comparison website. The city is a fascinating blend of ancient and modern. This UNESCO World Heritage site has an abundance of historic buildings as well as examples of innovative architecture, with fine Georgian houses and modern buildings such as the Scottish Parliament. The city is also known for hosting a variety of festivals and celebrations through the year. The Hogmanay (New Year) festivities are legendary, while the Edinburgh International Festival during August and September is the one of the biggest festivals of the arts and entertainment in the world, attracting both established and up-and-coming stars. Around Easter, there is the annual Science Festival, with a variety of events and talks featuring some of the biggest names in science, and in summer there is the Military Tattoo. Edinburgh's best-known landmark is its castle, which towers over the city from the steep Castle Rock. It has functioned as a castle since the 12th century, and has played a pivotal role in Scottish history. A popular attraction with an educational theme is Our Dynamic Earth, which traces the geological history of our planet through a variety of exciting interactive exhibits and 3D movies. Other attractions not to be missed include the National Museum of Scotland and the gruesome Edinburgh Dungeon, where a combination of actors and exhibits presents an early history of Scotland's penal system, recreating some particularly gory episodes along the way.