Wadi Al Hamadh (وادي الحمض) or Wadi Idham is one of the largest valleys of the Arabian peninsula, which is about 450 km long. It starts from the Medina area and runs north to the west to the northwest of Khyber when it meets the wadi gazelles. It then changes its direction to the west and crosses the mountains to the coastal plain to reach the Red Sea between the towns of Amlaj and Al-Jujah. And in some seasons it turns into a running river that may last more than 20 days without stop.
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