This is the most important imperial place in Japan, because it is the Japanese emperor house.
This place was used to be Edo castle from 1602 to 1868, so the imperial place has a long history.
This is the vestige of the castle tower, but it was burned in 1657, which was never rebuild, and now there is still the rock that was based on the castle tower, so as you can see from this picture, there are huge rocks.
This is the picture of castle tower in Edo era, but it collapsed. You could see that the imprial place is continuing from 1602.
This is the imperial place, and are used for some events. For example, on emperor’s birthday and New Year’s Day, and we can see it on TV like this.
Please check here! You can see the New Year's Day in the imperial place.
http://www.youtube.com/watch?v=nlv8pXRx5FQ
This is the Emperor house, and the Emperor really lives here now.
Last is aerial photograph. I researched the size, but it was too big, and I couldn't express it in English, but as you can see, it's very big. Moreover, the imperial place is surrounded by moat, in order to defend the castle against enemy in Edo era.
Recently, there are so many runners around castle. Because now imperial place is famous for power spot, so many people can excise with feeling some power.
So if you visit Japan, it is good to run around here. But please obey the runner rule.