They fell from the sky as written on 12,000 years old stone discs

There is much written about the mysterious extraterrestrial beings known as the "Dropa," described as extraterrestrial greys, who, around 12,000 years ago, experienced a crash landing on Earth in the Baian-Kara-Ula Mountains along the Chinese-Tibetan border. 

According to what may be the earliest version of the tale, in 1937 an archeological expedition in the Bayan Har mountains led by Chi Pu Tei found half buried on the dust floor a large round stone disc, in total they found 716 stone discs and each disc was 9 inches (22.7 cm) in diameter and 3/4 inch (2 cm) thick. Each disc also had an exactly circular 2 cm hole in its center. 

Besides the stones, the cavern walls where adorned with pictograms portraying our Solar System and intricate maps illustrating routes among the stars using intersecting lines and dots as well as remains of thin bodies with unusually large heads were also present at the site. 

Amazingly, not only all 716 granite discs, dated to 12,000 years before present, were filled with carved tiny hieroglyph-like markings, which, after decoding the markings in 1962, turned out to be a ‘record’ of alien writing composed of microscopic characters written in a language never encountered before . 

In 1966 further research has been conducted by Soviet researchers in Moscow who discovered that they contained large amount of cobalt and other metals, that they behaved as electrical conductors, and that they produced a humming sound when placed on a special turntable. 

It would have made it difficult for the primitive people to carve the lettering, especially with such minute characters. When testing a disc with an oscillograph, a surprising oscillation rhythm was recorded as if, the scientists said, they had once been electrically charged or had functioned as electrical conductors. 

The stone discs told the story of the Dropa people, space travelers from a distant planet whereby one stone disc had a thin spiral groove filled with hieroglyphics that told of the Dropa crashing their spaceship 12,000 years ago and they couldn’t repair their craft. Local Chinese (Han) killed off most of them and the survivors were those intombed in the cave. 

The Dropa stones have become a focal point of controversy, with numerous assertions suggesting that they might be nothing more than an elaborate hoax. However, when researchers visited the Banpo museum in Xian in 1994 where several discs were on display, they were informed by the museum director that higher authorities had mandated the destruction of the discs. Officially, the museum did not recognize the existence of these mysterious stones. 

This raises the question: were the 716 stone discs, purportedly bearing evidence of extraterrestrial visitation to Earth, truly unearthed, or is there a deliberate effort to conceal their discovery?