Upon witnessing such beauty on earth, what heart would not swell with joy?

Imagine seeing something so incredibly beautiful right here on Earth. How could your heart not swell with joy and pride? The poet is asking, when you encounter such stunning beauty, isn't it natural for your heart to feel a profound sense of happiness and wonder? It's a rhetorical question, suggesting that such an experience inevitably fills one with immense delight and a proud appreciation for the world's marvels. It speaks to the power of natural beauty to uplift our spirits and make us feel truly alive and connected to the wonders around us.