This is the 13695th most frequent Russian word.
неповторимый
Unique; unrepeatable.
The word 'неповторимую' here is an adjective, describing the characteristic of uniqueness or being unmatched for the feature of a culture.
Каждая культура имеет свою неповторимую особенность.
Each culture has its unique feature.
In this sentence, 'неповторимые' emphasizes the distinctiveness and originality of the art pieces created.
Этот художник создаёт неповторимые произведения искусства.
This artist creates unparalleled works of art.
Here, 'неповторимыми' is used to convey the idea that these family moments are precious and irreplicable.