Beijing has served as political centres for numerous Emperors. The fortification system first built in the city during Yuan Dynasty was thus used as a physical line of defence against intruders from all around China. It was later expanded and strengthened during the Ming Dynasty to underline the city's importance. However, when the Communist Party came into power, this protection system was rendered obsolete. Mao commanded for much of the walls to be demolished to make space for new buildings to be erected. Although no longer in their original form, city walls have left a great legacy for Beijing and its citizens. Today, the remnants of the fortification system attract tourists from around the world. They are reminders of the city’s past and give Beijing its unique layout. The recent construction of the ring roads serves as a physical continuation of the fortification system as they follow the original positioning of the walls, which wrapped around the Imperial City. While the city government has made much effort in restoring the ancient infrastructure, it is uncertain whether the walls will remain intact or be raved to make way for modernistic architecture. As Beijing now prides itself in its futuristic buildings and technological advancements, the role that its ancient past plays in its future planning will hopefully be one that combines the city's old values with new ideals.