Why must islamic believers travel to mecca once during their lives?

The islamic believers travel to mecca once during their lives because they perform Hajj ( Pilgrimage) which is one of the pilar of the islam.

Explanation:

First of all it is very important to know what is the Islam.

The Islam is an Abrahamic monotheistic religion teaching that there is only one god ( Allah) .

It is the world's second-largest religion with over 1.8 billion followers or 24 % of the world's population. By the other hand the mecca is the holiest of muslim city.

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.