"The extinct genus of sea turtle is a relative of the modern leatherback turtle," Gao says, adding that as far as she knows, the well-preserved skeleton with 70 percent completion is the only one in China.

Besides the turtle skull, a fossil of 21 trilobites showcasing rare preservation forms has been unveiled to the public. Trilobites, the first dominant form of complex life on earth, are a group of extinct marine arthropods that first appeared around 521 million years ago, shortly after the beginning of the Cambrian period, living through the majority of the Palaeozoic Era, for nearly 300 million years.

Gao says all the items on display have been carefully selected to give a glimpse into our planet's distant past.

As a popular attraction exploring life on Earth in the capital, the 23,000-square-meter museum has some 1.8 million visits every year. Meanwhile, a new location covering a total area of 57,700 sq m has been selected along the south of Beijing's Central Axis.