North India is culturally rich and diverse and is supported by very large cities: apart from the great metropolis of Delhi, the cities of Lucknow, Patna, Kanpur, Allahabad, Varanasi, Meerut, Jaipur, Chandigarh, Ludhiana, Amritsar, Jalandhar, Patiala, Srinagar, Jammu, Bhopal and Indore would rank with the most populous cities of Europe . The languages spoken in northern India, namely, Hindi (around 300 million), Punjabi (37 million), Bhojpuri (23 million) and others are classified by linguists as being Indo-Aryan languages. They differ from southern Indian languages which are classified Dravidian languages but share great similarities with western and eastern Indian languages. The key historical differences between northern and other regions of India is the influence of Islam and the interaction with Middle Eastern civilization through the ages. These influences can be understood by reviewing articles on Indian History and the Mughal Empire.