Most of the reviews of this I've read are fairly accurate - it's basically an enormous field surrounded by an original Roman flint wall, with a footpath running on top of the wall, but the main point of interest is the amphitheatre; a full intact example that you can walk all the way around at the top (although this path can be slightly precipitous,) and mooch around down on the arena itself. There are the usual information signs which are quite nice. The car park is free and has more information signs but be aware that the car park is the other end from the amphitheatre and church - it's worth driving round the other side and parking in the church car park if you want to see these two features in particular. On a Sunny day, its a very nice walk, but on a cold winters day it's all rather bleak and windy. However! the real time to visit Silchester is when Reading University's archeologists are doing a 'dig.' They do the dig every year and fill all the soil back in again, but when they are at it there is a student assigned to 'tourist duty' and if the foreman sees you he sends the student over to make you welcome and show you around the tent with all the artifacts they've dug up. I presume the dates can change each year so best to check with the university, but we happened upon this by chance and it added a lot of interest to our visit. The Red Lion pub isn't far away either and that's worth visiting as well just to experience the gigantic inglenook-type fireplace, and it also does meals and badger ale.
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