Why must practicing muslims travel to Mecca once in their lifetime?

Hajj is one of the Five Pillars of Islam. It is obligatory for every Muslim once in their lifetime, provided they are physically fit and financially capable. Hajj is performed over specific days during a designated Islamic month.

apart from forcing jews to live in ghettos, nazis also ensure forced labour for the jews.

the quality of life in ghettos was inhuman and very unhealthy.

those who lived in ghettos died due to starvation, or at times sent to concentration camps to be killed. they were forced to work for german reich, who was responsible for overlooking the daily proceedings at the ghetto.