It means that the balcony is high, and only by standing on the high balcony can we find the breadth of the earth.
Reference-the sky is high and the land is wide [ti ā n gā o DJI ǒ ng]
This ancient idiom comes from Wang Bo's famous poem "Preface to Wang Tengting's Autumn Farewell". The sky is deep and far away, and the earth is flat and vast.