Hi Hilary
Peterhof is not a problem, but the grounds and park are crowded on the weekend since that is a favorite park to visit by local Russians and their families. The Grand Palace is going to be a bit of a line to tour that but it is worth it. Go as early as possible because locals sleep in on weekends and don't show up until 12:00 or later.
Yes, the appointments bypass most of the lines but there are still a lot of organized tours using the same special entrance. Once inside, other than the Old Masters and French Impressionists sections, the massive size of the place swallows up the thousands of visitors inside. On weekends in front of a few dozen paintings will be the largest crowds.
The reports of dangerous water are highly exagerated. The new state of the art water treatment plant (which has an interesting Water Museum on its park like grounds) keeps water passing the international standards but locals still prefer bottled water or filters to alter the taste. It is not best tasting water but most locals use it for coffee and tea, washing and cleaning. There have been massive upgrades to the system but some old sections of town have pipes in the apartment buildings that have some rust in them. my own apartment is old, 1800, but the water is clear. All restaurants and hotels use filter systems for taste so it is perfectly safe for . Coffee is said to be better here by the locals who have visited other countries but do concede it is pretty good in Italy. They assume the Brits and Americans have no taste buds in their jokes about the famous "coffee" in those two countries. I don't know, I've never drunk coffee here or anywhere. Every country brags about their chocolate, ice cream, coffee and beer....and the beauty of their women. The ice cream is pretty good, but there is no question about the beauty of the ladies here.
A recent comprehensive survey of environmental rankings presented by US scientists in the USA at the recent G-8 conference listed Russia 32nd in the world and raising. The US was ranked 28th and falling trend lines.
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Avarice, envy, pride,
Three fatal sparks, have set the hearts of all
On Fire.