6 / 13
Farmers over-using fertiliser and failure to treat sewage have also been blamed for the algae invasion. (Rex)

Sea of green: Sunseekers relax in green algae which has engulfed Chinese beach

Huge swathes of blue-green algae have covered the beach in Qingdao, China. The bizarre sight is caused by algae called 'enteromorpha prolifera', which is non-toxic and keeps returning even though 20,000 tonnes have been removed in recent weeks.