Final answer:
The Palace of Darius I and Xerxes I is located in ancient Persia, present-day Iran, within the Persepolis complex. Persepolis was a grand construction project initiated by Darius the Great and was an important ceremonial center of the Persian Empire until its destruction by Alexander the Great.
Step-by-step explanation:
The location of the Palace of Darius I and Xerxes I is in ancient Persia, which corresponds to modern-day Iran. Specifically, these palaces were part of the Persepolis complex, an enormous and monumental construction project initiated by Darius the Great and continued by his son, Xerxes I. Persepolis is situated in what was known as the Persian Empire, covering a region from the Indus Valley to Northern Greece and from Central Asia to Egypt at its height under Darius I.
These palaces are significant examples of the grand architecture of the Achaemenid Empire, reflecting a blend of artistic styles from various regions of the empire and serving as a ceremonial center and seat of government. Persepolis, which means "city of Persians," was a strategically designed complex that utilized natural terrain and retaining walls to create a level terrace, which served as the government center and space for spectacular receptions and festivals. Unfortunately, the site was destroyed under Alexander the Great in 330 BCE but the ruins stand testament to the once-mighty Persian civilization.