Evidence shows that trade linkages with Europe began over 2,000 years ago: making Xi’an the oldest and arguably most important Silk Roads related site in China.
Emperor Wu sent a mission in 138 BC, originally to form a diplomatic alliance, but ended up planting the seed for further travels that would establish the Silk Road.
Meticulously planned, Chang'an, as is typical of most Chinese cities, was laid out like a chessboard and aligned on the cardinal points of the compass.