The estate in Aquitaine, which includes the 17th-century private castle of Marqueyssac and the romantic park, covers 22 hectares and includes winding paths through the vegetation, rock gardens, belvederes, waterfalls and theatres in the greenery. Special features of the site are the 150,000 hundred-year-old, hand-pruned box trees with their rounded, winding shapes that create an attractive natural spectacle. The park is open at various times of the year and on summer evenings is lit up with thousands of candles, making the atmosphere even more magical.

Quinta da Regaleira is a 4-hectare estate with a historic palace and park, located in the historical centre of Sintra and configured in its present form in the early 20th century. The gothic-looking complex includes exotic gardens, ponds, grottoes, labyrinths and temples, in a rich mix of architectural styles: from Manueline Gothic to Renaissance and Romanesque revivals. Several references to esotericism, Freemasonry, alchemy and classical mythology can be found: the Initiatic Well is the most relevant, a nine-storey spiral staircase penetrating down to 30 metres into the ground, where the Templar cross is carved at the bottom. After a plunge into darkness, returning to the light becomes the ultimate urge.

Commissioned by the wealthy entrepreneur and intellectual Eusebi Güell, who was impressed by the phenomenon of Anglo-Saxon garden cities, the park is the only built part of a larger urban plan to create a green suburb on the hills in the outskirts of Barcelona. The park, punctuated by buildings in sinuous, primeval shapes and bright colours, is an enthusiastic hymn to life and an example of the balance between architecture and nature, between the dreamy and the playful.

With a course of 2.75 kilometres lined with over 16,000 yew hedges, Longleat Hedge Maze near the village of Horningsham in Wilshire, England, is one of the longest mazes in the world. The 2.50m high hedges make it impossible to glimpse a way out, unless you activate your sense of direction or rely on chance. It is located in a 400-hectare park that also houses a safari park, a mansion and three other smaller mazes.

The Basque painter and sculptor Agustín Ibarrola conceived the "animated forest" or Bosque de Oma, within the Urdaibai Biosphere Reserve, as a manifesto of the relationship between nature and human presence. The polychrome traces painted on the trunks of the trees form geometric, anthropomorphic and zoomorphic figures, can be perceived in their entirety only from some precise points of view and could remain mysterious and incomprehensible to inattentive or unconscious viewers.

The 55-hectare park, located on the outskirts of Paris and among the largest in the city, is an important attraction from both an architectural and a scientific-cultural point of view. Its plan is generated by the overlapping of different geometric patterns, punctuated at their intersections by red structures called folies. In the area there are the Cité des Sciences et de l'Industrie, the largest science museum in Europe, the Géode, a hemispherical projection hall with a mirror surface, the Cité de la musique, a museum of musical instruments with a concert hall and home to the Conservatoire, the Zénith, a 6,300-seat arena, the Grande Halle, a space dedicated to fairs and events, and the Philharmonie de Paris (by Jean Nouvel), a symphonic concert hall with 2,400 seats. Entertainment gardens, such as the Jardin du Dragon with a large steel dragon and the Jardin de Bambou, attract visitors of all ages.

With a total area of 11,215 square metres, Peace Maze in Castlewellan is one of the largest permanent hedge mazes in the world and a symbol of peace for Northern Ireland. Planted with community involvement, the hedge includes 6,000 yew trees. The aim of the walk, which is about 3 km long, is to get to the centre of the maze where the peace bell, with its is auspicious tolling, stands.

A park that translates the complexity of different scientific theories into land art: this is how architectural and landscape designer and theorist Charles Jencks has conceived the garden at his estate in Portrack House, Scotland, where mathematical formulae and apparently ineffable subjects – such as the distortion of time and space caused by black holes – are narrated on a 12-hectare area amidst landscaping games of symmetries and curvatures, terracing, bridges and sculptures. The garden is private, opening to the public once a year as part of Scotland's Gardens programme.

The 40-hectare park nestled in the Scottish countryside, just a few miles from Edinburgh on the estate of Bonnington House, a 19th-century country house, is home to permanent installations, contemporary art and land art works by the most celebrated international artists and landscape designers, from Anish Kapoor, to Christian Boltanski, to Charles Jencks. In 2015, Benjamin Tindall Architects has designed two new buildings for service and exhibition spaces.

Nestled in the hills of Connemara, Brigit's Garden is an open-air museum inspired by Celtic mythology and the Celtic calendar, and is dedicated to Brigit, the goddess of fertility and springtime who was particularly loved by the Druids. The design of the site pays homage to the four great events of the Celtic year, which are represented in four natural areas: Samhain (winter), Imbolc (spring), Bealtaine (summer) and Lughnasa (autumn). A sacred path through the spiral of the seasons, among water lilies, coloured berries and symbolic plants, leads the visitor to explore with the senses the cycle of life in all its phases.

Located in Catalonia, this work is due to Josep Pujiula, a local resident, who started it in the 1970s, to rebuild it several times over the years (due to vandalism, fires and the construction of a railway) until it got to today's version (the fourth). Since 2014, the park has been open to the public and is regarded as a local attraction, amidst oddities and esoteric charms, such as 30 m high towers made of acacia branches, tunnels, mazes of crossed branches, rock carvings and anthropomorphic totems made of rusty metal.

This 18th-century garden complex is located on the Heligan estate in Cornwall. The gardens, considered by the 19th century among the most beautiful in Britain, fell into disrepair after the First World War (hence the name 'lost gardens') but were recovered in the 1990s as part of the largest green restoration project in Europe. The park with pavilions, ponds, grottoes and sculptures covers an area of about 32 hectares and includes Italian, English and exotic gardens. Among the most curious works are Mud Maid and The Giant's Head, sculptures that peep out of the ground among the trees and bushes.

If a garden gnome goes missing from time to time, one can assume its escape (or kidnapping) has brought it to Devon where Ann Atkin, an art scholar, has created a fairytale garden open to the public. The 1.6-hectare estate includes a wood, a stream, a pond, a meadow and a garden with some 250 species of wild flowers and ferns, where over 1,000 gnomes and elves have found their place.