Nanjing:

A monument to the huge human cost of some of the gigantic construction projects of the early Ming dynasty is the Yangshan Quarry (located some 15–20 km (9–12 mi) east of the walled city and Ming Xiaoling mausoleum), where a gigantic stele, cut on the orders of the Yongle Emperor, lies abandoned, just as it was left 600 years ago when it was understood it was impossible to move or complete it.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". Why was the stele abandoned?
it was impossible to move or complete it