Cradle of both modern Russia and Ukraine and of Slavic orthodoxy, Kyiv is known for the golden domes of its ancient churches and monasteries.
Both countries trace their origins to the medieval Kievan Rus empire which was centred on the city.
The capital of independent Ukraine since 1991, the city of 2.9 million people was long known by its Russian name Kiev.
It celebrated its 1,500th anniversary in 2001 and its 16th-century Kyiv-Pechersk Lavra monastery as well as the cathedral of Saint Sophia both figure on UNESCO's World Heritage list.
Kyiv's vast central Independence Square, popularly known as Maidan, became the centre of the "Orange Revolution" as well as the long pro-European uprising of 2014 that sparked Russia's annexation of Crimea.
Ukraine's second city is a predominantly Russian-speaking tech hub of 1.4 million inhabitants just 40 kilometres (25 miles) from the Russian border.
Heavily bombarded in recent days by Russian forces, it suffered badly in World War II when two major tank battles were fought around it.
Since 2014 it has become home to hundreds of thousands of people fleeing fighting between government forces and Russian-backed rebels in the nearby eastern Donbas region.
The key port city of Mariupol on the Sea of Azov has been under attack since Russia launched its invasion of Ukraine.
Mariupol was briefly occupied by the Russian-backed separatists from Donetsk at the start of the uprising against Kiev in 2014 before being retaken by Ukrainian forces.
The southeastern city of 441,000 people lies between territory held by the separatists and the Crimean peninsula, which was annexed by Moscow in 2014.
Russian forces claimed to have linked up with separatists Tuesday.
The Russian army claimed to have taken port of Berdyansk on the Sea of Azov Monday after advancing from Crimea. The resort of 115,000 inhabitants is famed for its beaches and mud baths, welcoming more than half a million tourists a year.
It is only 84 kilometres along the coast from Mariupol.
Kherson - which is being besieged by Russian forces from Crimea - is a strategic port on the west bank of the Dnieper River which controls the approaches to the Crimean peninsula.
Formerly the base of the Russian Black Sea Fleet, its fall would open the way to Odessa in the west, which has a majority Russian speaking population, and the borders with NATO-member Romania and Moldova. A shipbuilding city, it has a population of 287,000 people.