A lasting legacy?

I've been wandering around Rome for most of the afternoon, getting lost in a warren of side streets and being continually amazed at how much there is to see at every turn. Taking in the view from the Colosseum to the former Imperial Forum and the more than 2000 years of architectural history you can see as you look around is a very humbling experience. Any one of the churches, palaces or grand buildings that seem to line every street may well have a fascinating story to tell. Sometimes you can clearly see a new rococo entrance that has been stuck on top of a much older surrounding and there are so many styles and ages of building jostling for attention.
It made me wonder what the truly lasting legacy of this or any other city is - what do I remember of Rome, the sheer amazing history of all of it, the contrasts, one small perfect sunlit courtyard, the taste of a mouthful of pizza?
Two lines from the Psalms came to me as I was picking my way through the cobbled streets - trying to remember to look up and also look where I'm going (falling over is a speciality of mine). The first is from Psalm 8 which I love to sing in the beautiful traditional French setting:
⁴What are human beings that you are mindful of them, mortals that you care for them?
When confronted with the scale of the building in Rome it is hard not to feel that one's own contribution to history is pretty insignificant. At the same time though I had another verse from Psalm 90 going through my head and it's only since I've got home that I realise it must be a French translation that had become my inner version:
accorde-nous ton amitié,
et donne à nos travaux un résultat durable ;
oui, donne à nos travaux un résultat durable.

If I were to translate that back into English I suppose I might say something like:
"grant that our work may have a lasting impact"
Interestingly though the English translations and the Segond French translation say something rather different, with not quite the same force:
establish the work of our hands for us—
yes, establish the work of our hands. (NIV)
Affermis l'ouvrage de nos mains, Oui, affermis l'ouvrage de nos mains!
(Segond)
treat us with kindness
and let all go well for us.
Please let all go well! (CEV)

But as I was progressing around Rome and looking at all the extraordinary work of human hands I began to wonder if today it is still a prayer to pray - this idea that we should have impact, a lasting impression. Already my carbon footprint will have a lasting impact on the earth's ice caps, I surely don't want that kind of legacy. Of course I would in some way like to believe that I will have made some lasting contribution to the forces of good on our small green planet. I do rather hope that by the end of my life I may have learned to tread more lightly on the planet than I am doing at the moment.
But then Psalm 90 also has an even longer term perspective, the perspective of God's eternity. Even the mountains and seas of God's good creation are in constant life-giving, creative movement.
You turn us back to dust,
and say, ‘Turn back, you mortals.’
⁴For a thousand years in your sight
are like yesterday when it is past,
or like a watch in the night.

⁵You sweep them away; they are like a dream,
like grass that is renewed in the morning;
⁶in the morning it flourishes and is renewed;
in the evening it fades and withers.