Many countries have past history and the memories of the past stay with people as part of the culture.
Because
Boats and gold
It has allowed cultures to spread quickly and easily from one country to another.
Art is an expression. Certain elements of arts are cross cultural because all cultures have desire to express themselves with what each one has, and expressions may be similar to those of other cultures.
Amalgamation refers to a blending of cultures, rather than one group eliminating another (acculturation) or one group mixing itself into another (assimilation). Creative Biogene
cultural diffusion
The beliefs vary from one culture to another.
Cultures are created via the intermingling of different peoples over time. This means that the traditions of one group might diffuse through another based on their location. Therefore, each culture will have different traits from place to place.
The location of the empire was made up of the land of the Chavin, Nazca, and Moche peoples. Possibly these cultures had intervened with one another to form the Incan culture
The European and Muslim cultures before the crusades commonly traded with one another. This is the reason why they had large fleets of merchant ships.
No-one knows for certain
One main problem is the homogenization of local cultures, as popular culture from dominant countries can overshadow and diminish local traditions and identities. Another issue is cultural imperialism, where certain cultures dominate and influence others, potentially leading to the loss of diversity and unique cultural expressions.