How many five-star hotels are there in the world?

I am in the United Arab Emirates, and the Burj Khalifa in Dubai is 7 stars. Because of its shape, it is usually called the Sailing Hotel, also known as Burj Khalifa. I remember the last time I went to have morning tea with my leader, I had to make an appointment one week in advance. One person 150 dirhams/person.

This 8-star hotel is located in Abu Dhabi. It belongs to the royal family. Very little external.