Why go
The Aare runs through the town between the lakes, while the Lütschine comes out of the mountains to the south. Knowing that layout helps distinguish a westward Lake Thun day from an eastward Lake Brienz day, and makes the route toward the Jungfrau valleys easier to place on a map.
The full story
Interlaken's name refers to its position between lakes, but the town itself sits on the Bödeli rather than on both shores at once. The Aare connects Lake Brienz on the east to Lake Thun on the west. To the south, the Lütschine emerges from the mountain valleys, creating the natural direction for travel toward places such as Lauterbrunnen and Grindelwald. The lake basin did not always have this shape. Material carried down by the Lütschine and by the Lombach from the north gradually helped divide what had been a connected body of water after the last ice age. Interlaken, Unterseen and Matten now form a continuous settlement across this valley floor, even though they are separate municipalities. For visitors, that compact urban area can make the mountains seem close. The waterways and valley routes explain why reaching a lakeside landing or a high viewpoint still involves a deliberate journey beyond the central streets.