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The old castle of Nice is definitely a "must" for someone who visits the city. Regardless the stairs one has to climb (sometimes I thought they would never end), the park and the view of the whole city from up there is worth the trouble. There is an alternative of an elevator that takes you straight to the top, but I always prefered walking.
Once you reach the top, there lies a big park with a field and trees, the pleasant wind is redemptive and you can sit at any bench and enjoy. If you stroll around, you will find the remainings of what used to be a castle and a majestic waterfall that can be seen from the old city as well.
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