Muddy waters lap overfoot in Sanaa’s Old City, inhabited without interruption for more than 2,500 years but now facing disaster after floods that threaten the collapse of irreplaceable houses.

The deluge risks finishing off the destruction of its distinctive buildings with their ochre brick facades and white latticework windows, experts say. The foundations were already weakened by bombings in Yemen’s long war.

Flooding is common in Yemen at this time of year, blighting the poorest country on the Arabian peninsula that is in the grips of what the UN calls the world’s worst humanitarian disaster.

Torrential rains have also threatened other UNESCO heritage sites in Yemen, including in Shibam further east, renowned for its high-rise mud-brick “skyscrapers”.

“Sanaa is literally melting. The bombings which struck the town have made the foundations fragile. The rain has come to finish off whatever was left,” said Wassiei, who is also a member of a heritage protection group.

She called for more coordination between government and civil society groups involved in conservation. The work of those involved in protecting the nation’s heritage was being hampered by dysfunction and a lack of political will.

“The town appears to have been struck by what appears to be an unprecedented catastrophe.”

“Along with its international partners, UNESCO has been mobilising resources and expertise to safeguard Yemen’s cultural heritage by implementing a number of projects” including reconstruction and assisting local authorities, it said.