how to get to the great wall

Belinda, there is no direct subway that leads to the wall. You may take subway line 1 from Wangfujing Station to Fuxingmen station and then change line 2 to Xizhimen Station. Then walk to Beijing North Railway Station to take S2 train. The smart transportation card can be bought at the Xizhimen subway station. You can get some discounts if you use the card to board public buses.