By ITP
In Pictures: Yemen heritage architecture
Dar al-Hajar (Rock Palace), perched atop a rock pinnacle at the Wadi Dhahr valley, is 14 kilometres north of the capital Sanaa.

A general view taken on April 24, 2016 shows the Dar al-Hajar (Rock Palace), perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of the capital Sanaa. (MOHAMMED HUWAIS/AFP/Getty Images)

Yemenis visit the Dar al-Hajar (Rock Palace) perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of the capital Sanaa, on April 24, 2016. (MOHAMMED HUWAIS/AFP/Getty Images)

A general view taken on April 24, 2016 shows the Dar al-Hajar (Rock Palace), perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of the capital Sanaa. (MOHAMMED HUWAIS/AFP/Getty Images)

A Yemeni boy looks out from a balcony at the Dar al-Hajar (Rock Palace) perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of the capital Sanaa, on April 24, 2016. (MOHAMMED HUWAIS/AFP/Getty Images)

Yemenis visit the Dar al-Hajar (Rock Palace), perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of the capital Sanaa, on April 24, 2016. (MOHAMMED HUWAIS/AFP/Getty Images)

Yemenis visit the Dar al-Hajar (Rock Palace), perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of the capital Sanaa, on April 24, 2016. (MOHAMMED HUWAIS/AFP/Getty Images)

Yemenis visit the Dar al-Hajar (Rock Palace), perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of the capital Sanaa, on April 24, 2016. (MOHAMMED HUWAIS/AFP/Getty Images)

Yemenis visit the Dar al-Hajar (Rock Palace), perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of the capital Sanaa, on April 24, 2016. (MOHAMMED HUWAIS/AFP/Getty Images)

A general view taken on April 24, 2016 from a window of the Dar al-Hajar (Rock Palace), shows Yemenis visiting the palace which is perched atop a rock pinnacle at the Wadi Dhahr valley, 14 kilometres north of capital Sanaa. (MOHAMMED HUWAIS/AFP/Getty Images)