Final answer:
St. Petersburg, founded by Peter the Great in the early 1700s, is the city built as Russia's "window on the west". It was the capital of the Russian Empire and is known for its historical significance, cultural richness, and industrial importance.
Step-by-step explanation:
The city that was built by the tsar to be Russia's "window on the west" in the early 1700s is D. St. Petersburg. Peter the Great founded St. Petersburg to serve as a modern European capital for Russia and indeed made it the capital of the Russian Empire. The city was constructed with the aid of European architects and was intended to match the grandeur of other European capitals. Throughout its history, St. Petersburg underwent several name changes, becoming Petrograd and then Leningrad, before returning to its original name after the fall of the Soviet Union.
St. Petersburg is not only rich in history but also serves as a cultural center, a major tourist destination, and an industrial hub for the shipbuilding, oil and gas trade, manufacturing, and finance. Despite its beauty and importance, the city also witnessed tremendous tragedy during World War II when it was besieged by German forces, leading to a catastrophic loss of life among its civilian population. Its resilience and the continued reverence for its historical legacy make St. Petersburg an integral part of Russia's identity as a nation bridging Eastern and Western cultures.