I visited the Yungang Grottoes today 29.10, and my honest opinion is that it is worth visiting, but only if you enter exactly at 8:30 at the opening time. I arrived at the location today at 11 am, and it was full of people, I was pushed from all sides and I couldn't even enjoy anything. And besides all this, the grottoes from 16-20 were closed (probably renovation), it is best to inform yourself very well before arriving at the location.