Aperol is a low-strength aperitif made in 1919 but the Barbieri brothers in Padova.
It's a secret recipe including both rhubarb and bitter orange along with a wide assortment of herbs and roots.
The brand owner vowed to remain faithful to the original recipe. Immensely popular in Italy, it's home country.

Barbieri Aperol Details
Spirit Type: Liqueur
Country: Italy
ABV: 11%
Bottle Size: 700ml