What should I do in Lake Llanquihue and Puerto Montt,Chile?

I'm traveling with my girlfriend to visit my parents in Santiago. They know somone who has a house on Lake Llanquihue and want to take us there. I want to know the coolest things to do or see there. Any suggestions?

Been several times to Lago Llanquihue. First of all, the whole region is beautiful. Visit towns like Frutillar, Puerto Varas, Puerto Octay. In Frutillar you have wonderful german food, it was an old german settlement and there is a museum you should go. Puerto Varas has an enormous casino which is fabulous. Apart from visiting the towns, lago Llanquihue has the Osorno volcano just there, there are walks to the volcano and fishing expeditions (fly fishing) which you can contact via any of the travel agencies in Puerto Varas.
Puerto Montt is quite a big town and has lost its flavour (lots of malls, restaurants, etc) . I would rather stick to Puerto Varas, or Frutillar.
If you want to go some lake crossing, you can take the first part of the southern lakes crossing which is from Petrohue to Peulla. Petrohue has some amazing waterfalls and the scenary in the lake crossing is also amazing.
If you want some "action" at night, then stick to Puerto Varas' casino which is great.

Just have a great time.I don't think that country is fighting!Have fun.

Learn to fly fish and they go wild down there.

Beside Puerto varas(amazing) and frutillar, there are a lot of things to do in the area.

But first, the big cities of the area (Osorno and puerto Montt), aren麓t the coolest places to visit but still have some things to do. In Osorno, you can go to the dairies, or to the beach (yes, there is a beach, actually is a one hour trip to the area of bahia mansa and maicolpue, an area known only by the osornians, but is quiet and in the road there are little villages with native population, the mapuches). In Puerto Montt there is and area called Angelm贸, it麓s a fishing area, with a huge market ( a meal cost around 4US) and a lot of crafts , you麓ll find from ponchos to liquors.

But Puerto Montt is on the way to one of the most beautiful places in Chile: Chiloe island. The capital of the island, Castro, is 167kms away from Puerto Montt (including crossing the channel by ferry), but you won麓t be regretting that trip. Chiloe has an amazing tradition of myths and legends, for example the tale of El trauco, a demon that can make the single girls gone pregnant only by looking at them....yes, only in Chile....
but el trauco isn麓t the only thing that you will find in Chiloe. there are the fishermen麓s houses called palafitos, wooden houses that practically float on the sea, and the best seafood you麓ll ever try. And maybe if you麓re lucky, you麓ll run into a minga, a "ceremony" where the neighbours and friends help to a family to move their house to a different spot: they don麓t move the things from one house to another, they actually MOVE the house. the reward...probably a curanto (a typical food). Also try to visit the villages of dalcahue, curaco de velez an cucao, that one is a lake in the middle of the island, amazing for camping. But chiloe is a place to discover by yourself, that麓s only a little guide.

good luck in the south