Growing up I noticed the many electric substations in Lincoln, Nebraska. As time went by I became familiar with the voltages used in the area. Distribution voltages were 4-wire 12.47-kv/7.2-kv, 4-wire 4160-v/2400-v, and 4-wire 13.8-kv/7.97-kv. Subtransmission voltages were 24-kv, 34.5-kv, and 69-kv. I always thought these were 3-wire delta connected, but one person I know says the 34.5-kv lines were Wye connected. Transmission voltages I am familiar with are 115-kv and 161-kv, and I believe these were Wye connected.
My favorite substations tend to be the smaller 34.5-kv/4160-v/2400-v subs. However, just about any small substation where the utility is stepping down from a subtransmission voltage to a distribution voltage tends to attract my attention. These are called "distribution substations." Utilities like Otter Tail Power Company and Montana-Dakota tend to use 41.6-kv as a subtransmission voltage.