People tend to check in during these times:
Walk around the spire to visit three countries CH, DE and FR.
Visit 3 countries in 30 seconds! Proudly-hot tourist spot without barely any tourists.
Easily acceptable from Basel city centre via the 8 tram and a casual walk through the dockyards. Don't expect to stay long or see much of interest.
Three Country Corner, where Germany, France and Switzerland get intouch, but there is not much. At least a restaurant and a growing city part.