There are no recognized nations on Earth that have a name beginning with the letter X. Alphabetically, Vietnam precedes the letter X, while Yemen follows.
A famous city that begins with "x" is Xi'an, located in Shaanxi, China. Xi'an is the burial site of Emporer Qin Shi Huang who built an army of life-size terracotta soldiers, horses and chariots to guard him in the afterlife. The soldiers were discovered in 1974 and have been studied extensively for their artistry and construction; they may provide the earliest example of assembly-line manufacturing. Each soldier has unique facial features and was originally painted in bright colors that unfortunately faded when exposed to light.
Among the fictional places that begin with "x" are the mystical city Xanadu from Samuel Taylor Coleridge's unfinished poem "Kubla Khan" and the imaginary country Xanth, created by fantasy author Piers Anthony. Xanth occupies the same area as Florida but exists on a separate, magical plane of reality.