The awe-inspiring sight has, however, become increasingly rare in recent decades as long-line fishing has put species under threat of extinction.

Hysterectomies are becoming increasingly rare as new techniques are developed to treat a range of womb conditions.

Such tortoises are increasingly rare because they are frequently poached, and they are critically endangered in their native Madagascar.

But the film has an elegance, restraint and sense of space that is increasingly rare to find in documentary.

Caning by the head or housemasters was increasingly rare.