Once a year, during a thunderstorm, the Hattifatteners meet in large numbers at the deserted Hattifattener’s Island. They become charged up with electricity and start glowing, rocking back and forth, and gather around a blue pole with a barometer attached to it. In Tales from Moominvalley, Moominpappa travels with the Hattifatteners to the island. He then realises that the only thing that enliven the normally quiet, expressionless Hattifatteners is a great thunderstorm.

Moominvalley is surrounded by the Lonely Mountains, a high mountain range in the East, feared by many as an unknown and slightly scary area inhabited by the Groke. In the book Comet in Moominland, Moomintroll learns that a comet will be passing by Moominvalley and travels by advice of the Muskrat with his friend Sniff to the Observatory on the Lonely Mountains to consult the Professors. The Hobgoblin, a powerful magician in the book Finn Family Moomintroll, travels the universe with his flying panther, looking for the King’s Ruby. His top hat is found in the Lonely Mountains by Moomintroll, Snufkin and Sniff, who bring it back to the Moominhouse with unintended consequences.

Sniff’s cave has smooth walls, the floor is covered with soft sand, and a gap in the roof lets in some warm sunlight. Sniff finds his cave in the novel Comet in Moominland, and while waiting for the world to end, the Moomin family and their new friends hide in the cave together. In Finn Family Moomintroll, Snufkin hides the Hobgoblin’s hat in the cave. Shortly after this, to everyone’s dismay, the Muskrat unexpectedly moves into the cave, searching for a more quiet place to live.

Snufkin first appears in the book Comet in Moominland, when Moomintroll and Sniff encounter him in his tent by the riverbank. When they first meet, Moomintroll wonders why Snufkin would like to live in a place like that, to which Snufkin replies: ‘I wander about and when I find a place that I like I put up my tent and play my mouth-organ.’ Snufkin’s tent is yellow in Comet in Moominland, but is later described as green, for example in the book Moominvalley in November.

The Moomin family’s hammock is located in the Moominhouse garden. It’s the Muskrat’s favourite spot; he is often seen napping or reading his favourite book, The Uselessness of Everything, in the hammock. Also Moominpappa loves taking naps and enjoying slow summer days in the hammock.

The Moomins live in a round, blue house that resembles a tall ceramic stove (historically, the Moomins used to live behind stoves in people’s homes!). The house originally had only two storeys, but the numerous visitors quickly made it feel cramped, so Moominpappa extended the house into three storeys and a cellar. Moominpappa is very proud of the Moominhouse, which he built with his own hands. It has weathered storms and earthquakes, and is big enough for everyone to have their own room, including the many visitors and friends who become a part of the family.