Muslims across the globe are celebrating the start of Eid-al-Adha.

The festival marks the willingness of Ibrahim, known as Abraham in other traditions, to sacrifice his son for God.

It also comes as Muslims perform the hajj pilgrimage in Saudi Arabia – a mandatory religious duty that must be carried out at least once in the lifetime of all adult Muslims.

Nigeria Eid Al Adha
Nigerian Muslims offer prayers in Lagos (Sunday Alamba/AP)
Kosovo Eid al Adha
Kosovo men pray to mark the first day of Eid al-Adha outside the Sultan Mehmet Fatih mosque in Pristina (Visar Kryeziu/AP)
Russia Eid al-Adha
Russian police officers direct a congregation of Muslim believers leaving the annual celebration of Eid al-Adha in Moscow (Alexander Zemlianichenko/AP)
Egypt Eid al Adha
Muslims try to catch balloons distributed for free after Eid al-Adha prayers outside al-Seddik mosque in Cairo, Egypt (Amr Nabil/AP)
Afghanistan Eid al-Adha
Pigeons fly as Afghans prepare to offer Eid al-Adha prayers outside the Shah-e-Dushamshera mosque in Kabul, Afghanistan (Rahmat Gul/AP)
Palestinians Eid al Adha
Palestinian Muslims pray to mark the first day of Eid al-Adha, in Gaza City (Khalil Hamra/AP)
Philippines Eid al Adha
An enterprising Filipino Muslim brings out her sweets as she prepares to pray outside the Blue Mosque in Taguig, east of Manila (Bullit Marquez/AP)
Egypt Eid al Adha
Sheep toys are displayed for sale to mark the holy day (Amr Nabil/AP)
Pakistan Eid al Adha
Pakistani customers carry a goat they bought for Eid al-Adha in a rickshaw in Islamabad, Pakistan (B.K. Bangash/AP)
Iraq Eid al-Adha
A baker cooks Eid treats in Baghdad, Iraq (Karim Kadim/AP)