Moscow is worth visiting for two reasons...Red Square and the Kremlin. Red Square, initially a bustling marketplace, got its name from the Russian word for 'beautiful', which later came to denote 'red'. Our connection to the red color of the Soviet Union is incorrect and coincidental. The Red Square is known worldwide and contains two famous sites...the magnificent St. Basil's Cathedral (used in most references to Russia)...and Lenin's Tomb. Though not as awesome as being at the Pyramids in Egypt or the Roman Coliseum, standing in Red Square ranks in the top ten due to it's 'untouchable' status from the cold war days. The second site worth visiting is the Kremlin, a complex of buildings used to house the current Russian government along with beautiful churches...all behind an amazing fortress wall. You can actually enter the Kremlin walls and walk around freely (an unimagined event only 25 years ago). Once you have seen these two places, get on a train and head for St. Petersburg.
St. Petersburg was created by Peter the Great in the early 1700s and sits near the European border on the Gulf of Finland. Peter conceived of a city based on beauty and culture. He loved boating and had canals dug with the idea that all citizens would traverse the city by boat only. This didn't go over very well and was eventually overruled in years to come. To ensure the city was magnificent, Peter seriously suggested (basically ordered) all the wealthy Russian families to make an investment in St. Petersburg by building a palace there. Today St. Petersburg has over 2,000 palaces lining its streets and canals. The most famous of these is the Winter Palace, built by Catherine the Great to house her world class art and furniture collection. Today the palace is known as the Hermitage (based on her living there alone like a hermit) and is perhaps the best museum in the world (yes - even better than the Louvre in Paris). What makes the Hermitage so great is its 1,000 rooms, each in themselves unbelievably beautiful and unique. Another great palace is the Summer Palace, an hour drive outside of the city. Ransacked and nearly destroyed by the Nazis in the 1940s, the palace is slowly being restored to its previous beauty and is best known for the room of pure amber.
Moscow and St. Petersburg do have some unfortunate things in common... undrinkable water, so-so food and illegible signs (Cyrillic lettering). Very few people speak English and lets just say they make New Yorkers seem warm and friendly. Visiting these cities absolutely requires the companionship of someone who speaks Russian and preferably with a tour group. Entry to Russia requires a Visa, but no vaccinations.
Russia is known for its Vodka (I didn't try any), caviar (very good), amber (expensive), lacquered boxes (beautiful and expensive if original) and Matryushka dolls.
Russia is worth visiting, but only after you have seen most European cities and yearn for something different.