In this stretch of river, about 100 miles long, up to 200 billion fish are spawned every year, helping to make the 2,700-mile-long Mekong one of the most fish-rich rivers on the planet. Deep pools ...

Photos show the historic reintroduction, which is part of an ongoing project to bring back a species considered locally extinct for over 40 years.

From antiquity to modern times, the city has been rife with creatures that creep, slither, scurry and nest among its pillars ...