Answer:
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.