Laatzen is where Hannover's southern edge turns into the exhibition halls, a town of forty thousand, with the great fair grounds a few minutes away. The Expo of the year 2000 was held on this side of the city, and the vast halls and the odd, slightly futuristic pavilions that survive give the district a strange, half-empty feel on a quiet morning. It is a spot to meet and set off, not a place to linger.
South of here the Leine plain stretches towards Hildesheim, an agricultural landscape of sugar beet, wheat and wide skies, with the Harz mountains a faint blue line in the distance on a clear day. The villages, Pattensen and Sarstedt among them, are brick-built and low, with the odd church tower rising above the roofs. Pattensen has a small old centre with timber-framed houses and is a good place for a bakery stop.
The route from here heads to the Oker valley and the hills around Clausthal, which is the most interesting part. That means going from flat farmland to forested Harz mountains in a couple of hours, through Goslar and the Oker gorge, where the road follows the river between granite cliffs. The Harz has real hairpins, steep forested slopes and, in winter, snow, so plan the season accordingly. Spring and early autumn are best.
Traffic on the plain can be heavy, especially when trade fairs are on, and roundabouts and traffic lights come thick and fast. The bypass roads help, but there is no way to avoid the stop-and-start entirely. Fill up here, because the cities on the plain have plenty of fuel and the mountains have far fewer stations, and eat something before you leave, since you will be a while. Hannover is cheap and easy to leave, and the contrast with the hills is what makes the day. Just make sure you know which road you want before you join the motorway.