The world's best indoor gardens

Eden Project, Cornwall, England This helium-filled balloon takes Eden’s gardeners up to the canopy in the Rainforest Biome to prune trees. (Eden Project)

Phipps Conservatory & Botanical Gardens, Pittsburgh Phipps Conservatory and Botanical Gardens, a great steel and glass Victorian greenhouse, has been inviting visitors to explore the beauty and mysteries of plants since 1893. (Phipps Conservatory & Botanical Gardens)

Gardens by the Bay, Singapore Inside a 250-acre bayfront open space you'll find two of the world's grandest conservatories, showcasing the exotic flora of mountainous and semi-arid regions. Rather, they will soon -- the gardens open in June. (Gardens by the Bay)

Montreal Botanical Garden, Quebec The subarctic zone in the Montreal Botanical Garden Biodome is a rocky stretch of Labrador coastline, with steep cliffs. The temperature is kept relatively constant, between 12ºC and 15ºC and the duration of sunlight matches the natural cycle in the region.The biodome contains five different ecosystems, each representing a different region on Earth. (Ken Fallu/Montreal Botanical Garden)

Longwood Gardens, Pennsylvania This June, Bruce Munro, British artist and light designer, will debut an exhibition illuminating Longwood Gardens with large-scale, site-specific light installations. (Longwood Gardens)

Botanischer Garten, Berlin The acres (upon acres) of outdoor garden at this important green space may be in slumber for another few weeks or so, but inside the 1.5 acres of conservatory it's green as can be. (Botanischer Garten)

Garfield Park Conservatory, Chicago This secluded 100-plus year-old oasis is in a tough (but improving) corner of the Windy City's west side. (Garfield Park Conservatory)

The New York Botanical Garden, New York City Imagine Central Park, but with fewer people. And fancier landscaping. That pretty much sums up this green lung that beats at the heart of The Bronx, just a short ride on the Metro-North Railroad from Grand Central Terminal. (The New York Botanical Garden)

Yumenoshima Tropical Greenhouse Dome, Tokyo From carnivorous plants to the unique flora of Japan's Bonin Islands – sometimes referred to as the Galapagos of the Orient – it's all about the unusual at this multi-domed attraction on Tokyo Bay. (Yumenoshima Tropical Greenhouse Dome)

United States Botanic Garden, Washington, DC A beautiful conservatory built in the 1930s – designed by the same architect responsible for the nearby Capitol – is a winter highlight of this national garden, brightening up its corner of the National Mall and offering the fastest possible escape from a wet, cold DC winter. (United States Botanic Garden)