I've been planning a cycling holiday in London and wanted to make a short tour to the Royal palace/castle at Windsor. That got me thinking if other European countries have similar setup of former or current royal residences just outside of major cities?
The Palace of Versailles would seem to qualify. From the Wikipedia article:
The Palace of Versailles was the principal royal residence of France from 1682, under Louis XIV, until the start of the French Revolution in 1789, under Louis XVI. It is located in the department of Yvelines, in the region of Île-de-France, about 20 kilometres (12 miles) southwest of the centre of Paris.
The Palácio da Pena in Sintra, Portugal, probably counts as being "just outside of" Lisbon. According to the linked Wikipedia article:
[...] on a clear day it can be easily seen from Lisbon and much of its metropolitan area.
Saint Petersburg, Russia is known for having at least two royal palaces in the middle of the city (one hosts Hermitage and the other is Engineers' Castle), as well as multiple palaces just outside the city (still within legal boundaries): Konstantin's palace, the most famous Peterhof palace, Oranienbaum palace, Ekaterina's palace, Paul's palace and Gatchina palace (the only one outside legal boundaries).
Of course there are also quite a few minor palaces situated here and there.
It's not in Europe, but Iolani Palace in Hawaii is located in downtown Honolulu at 364 South King Street, Honolulu, HI 96813. The link above describes its location as,
Iolani Palace is located in downtown Honolulu, on the corner of King Street and Richards Street. The vehicle entrance to the Palace Grounds is located off Likelike Mall, on the left of King Street between the Palace and the Hawaii State Library.