Whisby Nature Park is a large wetland and woodland reserve west of Lincoln, created from former sand and gravel workings. The lakes, reedbeds, scrub, and bare sandy patches now support a wide range of birds and insects, making it one of the easiest nature escapes from the city.
It suits a low-key half day rather than a headline sightseeing stop. Use the waymarked trails, pause at the hides if you are birdwatching, and combine it with the Natural World Centre if you want facilities close to the paths.