Linked from
The 11 pages that link to Five Pillars of Islam, each with the reason it gives.
HajjNarrower topic: Hajj is the fifth pillar, required of those able to undertake it.
RamadanNarrower topic: Fasting in Ramadan is one of these foundational duties.
ShahadaNarrower topic: The Shahada is the first pillar in the customary Sunni list.
SawmNarrower topic: Sawm is the fourth pillar in the commonly listed Sunni formulation.
AdhanNarrower topic: The adhan summons Muslims to salah, one of the Five Pillars.
Fasting in IslamNarrower topic: Ramadan fasting is one of the five pillars.