Final answer:
In the 16th and 17th centuries, the Russian Empire expanded mainly across Siberia and against the Ottoman Empire in the south, reaching the Pacific Ocean and the Black Sea, setting the foundation for becoming a great world power.
Step-by-step explanation:
During the 16th and 17th centuries, the Russian Empire primarily expanded its control over Siberia, establishing settlements and trade routes. Under the rule of figures like Tsar Peter the Great, Russia's territories grew significantly. They pushed across Siberia towards the Pacific Ocean, and under Catherine the Great, they acquired fertile lands along the Black and Baltic seas. Later expansion continued into Central Asia, the Caucasus region, and even extended into Alaska.
As Russia expanded, it also engaged with other powers, like the Ottoman Empire, by undermining their control over the Balkans. The expansions during this period helped Russia become one of the most significant world powers by the 19th century, stretching its influence across immense geographical areas and establishing its presence as a formidable imperial force.