Masjid al-Qiblatain
Masjid al-Qiblatain (المسجد القبلتین) (Mosque of the two Qiblas) is a mosque in Medina that is historically important for Muslims as the place where a companion leading the prayer was told of the change of Qibla and did 180 turn he is said to have been commanded to change the direction of prayer (qibla) from Jerusalem to Mecca. Thus it uniquely contained two prayer niches (mihrabs). Recently the mosque was renovated, removing the old prayer niche facing Jerusalem and leaving the one facing Mecca.
It is said that while the prayer was in progress directing Jerusalem Prophet was desiring about praying toward Mecca. But he can not make this decision by his own. He was looking upward. Then Gibril came with divine message that God has granted his wish to change the direction (Qibla) towards Mecca. Prophet Muhammed did it and everybody followed him and finished rest of the prayer directing to Mecca. Thus this prayer and mosque witnessed two directions (Two Qibla or Qiblatain).
Other links:
Al-Masjid al-Nabawi
Imam Hussein Shrine (part1)
Imam Hussein Shrine (part2)
Al Abbas Mosque
Fatimah al-Masoomah Shrine