Forming the southern end of the Balkan Peninsula, Greece extends between the Aegean Sea to the east and the Ionian Sea to the west. There are numerous islands, large and small, on all sides of the mainland that belong to Greece. Emerging between 2500 and 1500 years BC, Europe's first advanced civilisations (the Minoan on Crete and the Mycenean on the mainland) are Greek in origin. Democracy, Western philosophy, literature and mathematic principles also have their roots here. Rising out of the Aegean, on the west side of the mainland, Mount Olympus (2971m / 9570ft) is the country's biggest mountain and provides an excellent objective for a 1-week trekking holiday. Over 250 kilometres long, Crete is the biggest of Greece's islands in Greece and lies in the southern part of the Aegean Sea. It is a mountainous island with lots of potential for walking holidays. Far from the popular tourist areas, it is the White Mountains (or Lefka Ori) in the west that offer the wildest experience, with classic walks through the Samari Gorge and up to the high point of the range at remote Pachnes.