There is quite a bit of irony in the fact that the pilgrimage to Mecca represents a form of idol worship, one of the cardinal sins of Islam. The black Stone, held in the Kaaba, represents the centre of the Islamic world. Most pilgrims will try desperately to touch and kiss The Stone as they circumambulate the Kaaba. This ritual is probably a legacy of pre-Mohammedan animism.
Some Hindus have suggested from the color and shape of The Black Stone, that it is essentially a Shiva Lingam, perhaps initially worshipped by Hindu traders to Arabia or brought over by Arabs themselves to worship. Either seems possible as the most sacred and oldest Shiva temple in India, Somnath, is located on the West coast of the most Western of India's states, Gujarat, which was and continues to be a major trading partner with the Arab world.
Like Muslims circumambulating the Kaaba, Hindus worship Shiva by walking around the Shiva Lingam. It would be ironic indeed if billions of Muslims through the centuries have been worshipping Shiva.