Here's two links today that give a very interesting overview of GSM, UMTS and LTE coverage in Germany today from two of the four network operators. I've chosen to link those two, because Vodafone and T-Mobile have built up significant LTE coverage over the past 18 months, especially in rural areas to bring high speed Internet coverage to small towns and villages. This was part of the license conditions for the 800 MHz digital dividend band and as can be seen on the maps it has born fruit.
On the T-Mobile map one can also see LTE coverage that will be switched on soon, most of it in big cities this time. The special thing about the Vodafone map is that UMTS and LTE coverage can be shown separately or together on the map and it's interesting to observe how LTE fills the gaps in UMTS coverage.
I've been saving screenshots those coverage maps for years and it is quite interesting to see how 3G coverage expanded over the years. Initial 3G deployments looked quite different from the initial LTE deployments now as at that time, it was the big cities that were covered first rather than rural areas. This time around, license conditions have made the picture different and also, 3G in big cities with HSPA+, 64QAM and Dual Carrier extensions still has ample capacity to serve the needs there so there was no disadvantage to go for rural coverage first where often, only 2G was available.