Greening the walls and roofs of our buildings 绿化建筑的外墙和屋顶
Once inside the city walls, they head for one place. 一旦穿过城墙 它们就直奔目的地
And the walls had one further surprise. 而石壁上还有更惊人的发现
The walls were covered with the most delicate and fragile crystals. 石壁上布满了光洁美丽的脆弱结晶
which spend part of their day resting on cave walls. 它们一天大部分时间都呆在洞壁上
The bats roost high on the walls and ceilings 这些蝙蝠倒挂在洞壁和天顶上