Once an open stretch of the Mediterranean, Monaco’s Mareterra district is now a thriving new neighbourhood built entirely on reclaimed land. Unveiled in December 2024, the €2bn development expands the world’s second-smallest country by 3%, offering a blueprint for sustainable urban growth along fragile coastlines. With green infrastructure, architectural ambition, and Mediterranean charm, Mareterra redefines luxury living though not without raising questions about accessibility and environmental impact.
Engineering a City Out of the Sea
For a nation with only 2.2 square kilometres of land hemmed in by France and sea, Monaco’s long-standing solution to expansion has been to push into the water. Since 1907, a quarter of Monaco’s territory has been reclaimed from the sea. Mareterra, located near Larvotto beach at the eastern end of the principality, is the latest and most technically advanced project in this legacy.
The foundation of Mareterra rests on 18 colossal caissons each weighing 10,000 tonnes and standing 26 metres high designed to act as a breakwater while housing advanced wave-dispersing structures. These hollow concrete chambers include Jarlan systems with vertical openings above the waterline, allowing waves to enter and dissipate energy safely within, even during rare 100-year storms.
“When the sun shines through the openings in the Jarlan chamber in the morning, there’s a slightly blue hue to the space,” said Guy Thomas Levy-Soussan, managing director of SAM L’Anse du Portier, the project developer.
A Sustainable Urban Vision
Named Mareterra “sea and land” the six-hectare extension includes two residential buildings (one designed by Renzo Piano), 10 villas, four townhouses, a marina, and 14 commercial spaces. But its most striking aspect is its commitment to sustainability. The district integrates:
- 9,000 square metres of solar panels;
- 200 electric vehicle charging stations;
- 800 trees and three hectares of public green space.
Landscaped paths like La Pinède weave through Mediterranean pines, rock gardens, and water features designed to attract local fauna. Marine life, too, has been considered: specially textured caissons support biodiversity, encouraging sea flora and fish to recolonise the underwater structure.
Preserving a Delicate Ecosystem
Environmental efforts included a groundbreaking transplant of 384 square metres of Posidonia oceanica, a vital seagrass endemic to the Mediterranean. Normally moved plant by plant, the Mareterra team used a modified tree spade to scoop up large sods of seagrass, sediment and root structures intact, and replant them nearby.
“We took the Posidonia along with its entire root ecosystem,” said oceanologist Sylvie Gobert. “That’s what made it innovative.”
Architecture Meets Everyday Life
At street level, Mareterra has quickly integrated into Monaco’s coastal fabric. It borders the Japanese Garden and the Grimaldi Forum both of which have been expanded thanks to the new land and features an 800-metre pedestrian path, Promenade Prince Jacques, lined with sea views and shaded benches. Locals jog, picnic, and meet under Quatre Lances, an Alexander Calder sculpture once relegated to storage, now restored as a focal point.
Restaurants like Marlow, the principality’s first British fine-dining venue, and boutique outlets add to the character, while more meditative attractions include La Grotte Bleue, an atmospheric concrete cavity named for the Blue Grotto of Capri. A few doors down is a lavender-toned meditation chamber by artist Tia-Thủy Nguyễn. The effect is less glitz, more calm an unexpected vibe for Monaco.
When to Visit and What to Know
- Best time to visit: Late June or early September for good weather and fewer crowds. Avoid May unless attending the Grand Prix.
- Where to stay: Hotel Metropole, reopening in 2025 with a Guerlain spa and refurbished suites, offers prime access to Monte Carlo.
- Dining options: Try Marlow for upscale British cuisine or Sexy Tacos at Larvotto for a relaxed beachside meal.
Who Is Mareterra Really For?
Despite its green credentials and public access, Mareterra has drawn criticism over its exclusivity. Real estate prices are expected to start at €100,000 per square metre, making it among the most expensive properties in the world. None of the homes have been allocated for Monaco’s 10,000 Monegasques, who are entitled to subsidised housing, raising questions about the project’s public benefit.
“Though it’s pitched as a housing solution, it’s not solving local affordability,” notes journalist Nancy Heslin. “But Prince Albert sees expansion as progress without building, the country stands still.”
A Model for Coastal Innovation?
Mareterra may not resolve Monaco’s housing crisis for everyday residents, but its innovations in marine conservation, land reclamation, and sustainable urbanism offer lessons for coastal cities facing rising seas and shrinking land. With the technical expertise to pull off the extraordinary, Monaco continues to position itself as a laboratory for forward-looking development.
“As long as there’s ambition and budget,” said Levy-Soussan, “Monaco will keep redefining what’s possible.”
