Petrovsky Palace is a boutique hotel now. It was built for Catherine the Great in 1776-1780 but only visited the palace once in 1785.
Another royal guest was Napoleon, who was fleeing from a burning Moscow in 1812.
Via Google Streetview, you can roam around outside and inside the Palace.
Via Google Streetvieuw you can roam around outside and inside the Palace.
If you want to spend the night, you can check prices and availability here.