God is everywhere and is part of everything . The Vedas say the entire material Universe with its energy is formed out of only a small part of God.,and all matter , energy , objects animate and inanimate , living and non living are part of the Infinite Spirit.
So the realized soul sees God in all things . For most ordinary people however , the Divine is more easily felt and experienced in some small way, ( at the very least) at some places compared to others . These places are sacred , and include ancient temple towns , Teerthas ( points at rivers where ritual bathing is spiritually uplifting , ) ancient places of religious significance etc .
The indian subcontinent is dotted with hundreds of such places , indicating the importance of the Sanathana Dharma's role in defining the nationhood of India .
The seven ancient sacred cities is one example of a list .
These cities are important pilgrim centres , but only a few of many examples .
Another list called Char Dham ( the four holy places ) in four corners of India is
1. Badri Kedar in the himalayas
2. Puri in the East
3. Dwaraka in the West
4. Rameshwaram in the South
The Himalayas has its own list of Char Dham
The Sri Vaishnava followers of Sri Ramanuja , have a list of 108 very important sacred temples to Vishnu ( as sanctified by the poems of 12 mystic tamil saints called Alvars ) .
Saivaites ( followers of Siva ) have a list of (Dwadasha Lingas ) twelve temples spread all over india.
Another list comprises of 274 temples of Siva (as sanctifed by the 64 tamil saints called Nayanmars )
Worshippers of the Divine Mother , called Shakti , Durga , Amman etc also have there own lists .