MOUNTAINS of the world.Aravallis are aligned in north-east to the south-west direction and STRETCHES through the states of Delhi, Haryana, Rajasthan and Gujarat. Aravalli is 700 kilometers-long mountain range that starts from India's western state of Gujarat.The Aravalli Range is an eroded stub of ancient mountains.The highest peak is Guru Shikhar which is elevated at 1,722 metres. Fold mountains are formed when two of Earth's tectonic plates are pushed together within the earth's upper crust.There are two types of fold mountains: young fold mountains and Old fold mountains e.g. of the USA.Young Fold mountains:They are of recent origin.They are higher than the old fold mountains.Examples include the Rocky Mountains, Andes and Himalayas.Old fold mountains:They have formed years ago.They are lower than the young fold mountains.These have gentle slopes.The Ural Mountains, Aravali ranges and Appalachians are examples of old fold mountains.The three parallel ranges of the Himalayas longitudinal extent are: Himadri (Great or Inner Himalayas):The northernmost range is called the Himadri and extends for about 2400 km.Mt. Everest and Mt. Kanchenjunga are a part of these ranges.Himachal (LESSER Himalayas):It lies to the south of Himadri. Some famous ranges are the Pir Panjal range, Dhaula Dhar and Mahabharat ranges. It has some famous valleys like Kullu, Kangra and Kashmir. Shivalik (Outer Himalayas):This is the outermost range of the Himalayas. SHIVALIKS are known by different names in different areas such as Dafla, Miri, Abor and Mishmi Hills in Arunachal Pradesh. Western Ghats:Western Ghats range extends from river Tapti in Maharashtra in the north to Kanyakumari in the south.The Western Ghats are known as Sahyadri in northern Maharashtra, Sahya Parvatham in Kerala and Nilagiri Malai in Tamil Nadu.The Western Ghats runs through six states i.e Gujarat, Maharashtra, GOA, Karnataka, Tamil Nadu, Kerala and two Union Territories i.e Dadra & Nagar Haveli and Pondicherry.Anamudi in Kerala is the highest peak in the Western Ghats and is located on Anaimalai hills.The Western Ghats and the Eastern Ghats are connected at Biligirirangan Hills in Karnataka.The Eastern Ghats are a discontinuous range of mountains along India's eastern coast.The Eastern Ghats spread over the states of Odisha, Andhra Pradesh, Telangana, Karnataka and Tamil Nadu.