Salaam!
I heard that Guru Nanak the founder of Sikhism went to Makkah and Madinah, is that true? I heard that kaafirs are not allowed in these two cities…
Better way to put is that non-muslims are not allowed in mecca and Medina. Islam allows non-muslims at these places but due to political and security reasons non-muslims are barred from entering these places.. though many non muslims christians and people of other belief have entered and even performed hajj.. there were no passports or identification so there were fewer checks.. these peopel went to seek knowledge.. guru Nanak actually did hajj and was inspired by Islam..sikhism is a religious movement trying to seek a path between hinduism and Islam.. sikhs believe in one God so terming them kafir is debatable!