It is really easy to enjoy a nice walk in the nature even when you are in Bratislava; e.g. you can visit Sandberg – situated in Devin which is a borough of Bratislava, 12 km away from the city center. The abandoned sandpit is a paleontological site taking area of more than 25 ha, with the remains of the sea sands older than 14-16 millions years. The protected site is extremely rich in fossil remains of marine coastal and terrestrial fauna and flora. More information about the area is available here.
From Sandberg you can walk a nice path leading to the Devínska Kobyla hill and lookout tower. The forest path marked with green color is really beautiful and will take you all the way to the top. Devínska Kobyla hill (514 m) is the highest point of Bratislava. The lookout tower you find at the top of the hill is 21 meters high. You need to conquer 112 steps to get to its highest platform.
The map of the stroll is available here.
And if you manage to climb all the way to the top of the hill and then to the top of the lookout tower, you will be able to enjoy beautiful views. And if you do so just before the sunset, even the suns last rays setting behind the horizon.