Nhi Thanh Grotto is situated in Nhi Thanh Street, approximately 1km from the Lang Son City, Lang Son province. It is home to the Pagoda of Triple Regions (Buddhism, Taoism, and Confucianism). The grotto was closely related to the celebrity Ngo Thi Si when he was the chief of province between 1777 and 1780. He gave, in a short span of time, a new look to Lang Son in term of politics, economy and national defense. Especially in the domain of culture, he had the merit to discover 8 beautiful landscapes of Lang country including Nhi Thanh Grotto. He hired workers to start the renovation of this grotto in 1779. The right side area, being on a relatively more elevated land and the configuration of terrain better, was chosen to be the place for the building of the Pagoda of Triple Regions (in honour of Confucianism, Taoism, Buddhism).
Being a natural cave, Nhi Thanh Grotto lies beneath the Pagoda of Triple Regions, with the depth of 600 meters. On the cliffs at the entrance are 20 inscriptions that are precious historical and literary documents, including autographs of famous scholars. The statue of scholar Ngo Thi Sy on the cliff engraved in 1779 is a precious work of art. The length of a corridor from front entrance to back entrance is over 500 metres with many beautiful and picturesque landscapes. Inscriptions can be seen today on grotto, which were engraved by famous personalities and poets over different epochs.
Moreover, the grotto has numerous stalactites and stalagmites in different shapes, making the grotto look more grotesque and mystical. The entrance to the grotto is almost obscured from sunlight, because it is covered with dense foliage of trees. High on the wall to the right side of the entrance, there remains a poem carved deep into the stone. The poem was written by Ngo Thi Si (1726- 1780) when he was stationed in Lang Son as the commander of the Lang Son military post. Ngo Thi Si praised the beauty of the magnificent mountain and landscapes possessed by Lang Son. Ngo Thi Si was the person who discovered Nhi Thanh Grotto. The name Nhi Thanh was chosen by Ngo Thi Si to commemorate his birth place in Ta Thanh Oai village in Thanh Oai district, Hanoi. To commemorate his great contributions to the grotto, Ngo Thi Si had his portrait carved on an interior wall.
"Flows of clean pure white stream water run over hundreds of pieces of marble as if it is talking. Turn one's back to the stream and look up to a high mountain peak in the from can see the Vong Phu peak". Ngo Thi Si’s verses make you feel like to visit Lang Son’s beauty spots, and Nhi Thanh Grotto is one of the eight sites that attract a large number of visitors to Lang Son.
