Oneness of India

From where this oneness of India irrespective of invasions from hunas,monglias, mughals and british comes ?The answer is plenty. Pandit Jawaharlal in one of his speeches said that “the aspiration of north Indians to visit places in south like madhurai,thirupathi,rameswaram guruvayoor and south Indians to visit kasi,kailash,haridwar,ganges. Makes the people of India a feeling of oneness .