Suddenly, it feels like everywhere we look an egg-shaped structure is popping up. From a mirrored, golden sauna to a perfectly oval, wood-shingled tree house, each one is unique in its own way. Intrigued? There are even a couple companies offering these cozy capsules for sale.

1. Pigna Tree Houses in the Italian Dolomites

The Pigna tree houses were created by Tarvisio-based architect Claudio Beltrame in collaboration with DomusGaia, an Italian firm that manufactures wooden prefabricated homes. The team developed the dwellings for an architectural competition in 2014, and they're now available as holiday rentals.

2. Arctic Cabin in Hammerfest, Norway

This 150-square-foot cabin gives hikers a comfortable place to rest and recharge while hiking through the rugged, unspoiled beauty of Hammerfest, Norway. The region was previously inaccessible due to its challenging terrain and harsh climate, so the Norwegian Trekking Association developed plans for a “day trip” shelter in collaboration with SPINN Architects and Format Engineers to encourage exploration. This unique egg-shaped structure, dubbed the Hammerfest Cabin, is the result.

3. Egg-Shaped Camping Pod in the Loire

Architects Aurélie Poirrier, Igor-Vassili Pouchkarevtch-Dragoche, and Vincent O’Connor took inspiration from French naturalist Émile Plocq when they created this egg-shaped camping pod. Mr. Plocq’s Caballon is located on the banks of the Loire estuary.

Inspired by the Plocq's expeditions to Africa, the pod has a naval vessel’s wooden hull, with a cockpit-like top half that is covered in white canvas and clear plastic, so guests can enjoy a view of the stars as they sleep. The team built the 161-square-foot structure for the annual Imaginary Nights event hosted by Loirestua, the local tourism board, which allows visitors to stay in extraordinary quarters along the Loire estuary.

4. A Golden, Egg-Shaped Sauna in Sweden

Sweden’s northernmost city, Kiruna, sits above a giant iron ore mine owned by the state-run mining company Luossavaara-Kiirunavaara Aktiebolag (LKAB). Over a century of industry has endangered the stability of the location, so in 2004, city officials resolved to shift the entire city about two miles east.

To commemorate the move, Swedish housing cooperative Riksbyggen enlisted internationally-acclaimed artists Mats Bigert and Lars Bergström to create a public art installation. The resulting Solar Egg is an ovoid sauna constructed out of 69 polygons of gold-plated stainless steel. Inside, a heart-shaped wood-fired burner heats the fully-functional sauna. Stateside sauna fans now have a chance to check out the Solar Egg, as it will be installed in downtown Minneapolis from March 6 to April 28.

5. Egg-Shaped Beach Cabins in Korea

Korean studio Yoon Space designed these white, egg-shaped pods for easy mobility. The tiny seaside cabins, which the firm calls “Albang,” are only 21 square feet long. The pods are hand-whittled from blocks of polystyrene, making them light enough to be easily transported.

6. An Egg-Shaped “Blob” For Sale in Belgium

Belgian firm dmvA originally designed this egg-shaped “Blob” as an office space for a client. However, when the firm was unable to obtain a building permit, they redefined the mobile unit as an “art object” in order to skirt strict building regulations.

The small, smooth egg may be compact, but it is designed to house everything you need: a bathroom, a kitchen, lighting, a bed, and even storage. You can even order a Blob of your own (price available upon request).

7. Egg-Shaped Houseboat in Hampshire, UK

The Exbury Egg is an egg-shaped, energy-efficient, self-sustaining workspace built for British artist Stephen Turner. Turner worked with Space Placemaking and Urban Design and PAD Studio to develop the Egg, which was set in the River Beaulieu estuary on Exbury Estate, Hampshire, UK.

The team developed the Exbury Egg as an artwork, a temporary place for Turner to stay, and a laboratory for studying the life of the tidal creek. Over time, it took on the patina of the daily tides and over 18 months of weathering by wind, rain, and the sun.

8. The Self-Sufficient, Egg-Shaped Ecocapsule

The Ecocapsule is a smart, self-sustaining micro-home that is entirely powered by solar and wind energy. The vessel is designed to enable residents to explore remote locations with the luxury of their very own micro hotel room.

Related Reading: A Fantastic Egg-Shaped Camping Pod Along the Loire Estuary, This Egg-Shaped Cabin Provides Shelter for Arctic Circle Travelers