One of the most popular tourist destinations in Umbria is the Basilica of St Francis of Assisi where many famous and less famous painters works are still preserved even if the most important decorations are the series of frescoes ascribed to the young Giotto

Can you repeat this sentence, but add in punctuation?
One of the most popular tourist destinations in Umbria is the Basilica of St Francis of Assisi, where many famous (and less famous) painters' works are still preserved, even if the most important decorations are the series of frescoes ascribed to the young Giotto.