Information: In Turkestan, on the right bank of the Amou Diara, in a chain of rocky hills, near the Bokharan town of Karaki, are a number of large caves which, upon examination, were found to lead to an underground city, built apparently long before the Christian era. According to effigies, inscriptions and designs upon the gold and sliver money unearthed from among the ruins, the existence of the town dates back to some two centuries before the birth of Christ.
The underground Bokharan city is about two versts long and is composed of an enormous labyrinth of corridors, streets and squares, surrounded by houses and other buildings two or three stories high. The edifices contain all kinds of domestic utensils, pots, urns, vases and so forth. In some of the streets falls of earth and rock have obstructed the passages, but generally the visitor can walk about freely without lowering his head. The high degree of civilization attained by the inhabitants of the city is shown by the fact that they built in several stories, by the symmetry of the streets and square, and by the beauty of the clay and metal utensils and of the ornaments and coins.
A similar (later) article has slightly different information. It appears this story appeared several times in different newspapers in 1895, but I haven’t been able to find any information on the original expedition.