Ukraine is a country in Europe.
During the late 8th to late 11th centuries, the Vikings raided and traded from their Scandinavian homelands across wide areas of northern and central Europe, as well as European Russia. One of these raid routes took them near Kiev, Ukraine. In the 21st century, this particular route was considered by Skye as one of the possible locations for the Berserker Staff, as Elliot Randolph suggested searching Viking routes for its possible location.
In the 13th century, Genghis Khan was able to rule one of the greatest empires of history, from the Pacific to Ukraine, thanks to the use of the bow an arrow. At the beginning of the 21st century, Raza, a member of the Ten Rings, referenced this fact telling Tony Stark that the weapons from Stark Industries have become the key to ruling lands.
World War II
Kidnapping of Nikola
Leviathan obtained the blueprints for a Photonic Amplifier designed by Howard Stark, but as its construction was difficult, they needed a qualified engineer to built it. Leviathan kidnapped a gifted engineer named Nikola in Kiev, taking his family as leverage and imprisoning him at the Red Room Academy to force him to construct the weapon.
In 2009, Natasha Romanoff was tasked with escorting a nuclear engineer out of Iran. Upon reaching the city of Odessa in Ukraine, they were attacked by the Winter Soldier, who made them lose control of their vehicle and fall off a cliff.
Romanoff managed to pulled the engineer and herself out, but the Winter Soldier, who was waiting for them, shot through Romanoff's stomach and killed the engineer.
Five years later, Romanoff reached some of her contacts in Kiev in order to obtain a file regarding the Winter Soldier, that included a photograph of Bucky Barnes inside a Cryostasis Chamber, and notes about his transformation into the Winter Soldier.