Why did Darius fill Persia's capital city in gold silver and artwork?

Darius filled Persia's capital city, Persepolis, with gold, silver, and artwork to symbolize the wealth and power of the Persian Empire. This opulence was intended to showcase the empire's prosperity and attract visitors, reinforcing Darius's status as a formidable ruler. Additionally, the grandeur of the city served to unify the diverse cultures within the empire and project an image of stability and strength to both subjects and rivals. Ultimately, it was a statement of imperial pride and ambition.