Most Challenging Pillar For Muslims

     The one pilar that I think was the most challenging for the Islams was the last pilar. That pilar was that all Islams had to go to Muslim at least once a year. I think that one is the most challenging because lets say a believer of Islam lived in a desert, how will they have a transportaion to get there? 
     Some of you guys might not agree with me, but the rest of the pilars all have to do with praying, fasting, believing in just one god, and reading the bible. I belive that those are very important than any others.