The New York Botanical Garden (established in 1891) has been described as the “crown jewel of the Bronx.” The NYBG’s Enid Haupt Conservatory is sometimes called the “crown jewel of the Bronx” or the “crown jewel” of the NYBG.
 
“The New York Botanical Garden’s crown jewel, its Victorian ‘crystal palace’ conservatory” was cited in print in 1994. “The crown jewel of the Bronx, the New York Botanical Garden consists of 250 acres of horticultural wonders” was cited in 1998.
 
     
Wikipedia: New York Botanical Garden
The New York Botanical Garden (NYBG) is one of the premier botanical gardens in the United States, located in the Bronx in New York City. It spans some 250 acres (100 ha) of Bronx Park and is home to some of the world’s leading plant laboratories. It offers major exhibitions and flower shows throughout the year, drawing over 800,000 visitors annually.
 
WIkipedia: Enid A. Haupt Conservatory 
The Enid A. Haupt Conservatory is a greenhouse in the Bronx, New York, United States, a major part of the New York Botanical Garden (NYBG). Inspiration for the park and the conservatory stemmed from Nathaniel Lord Britton and his wife Elizabeth. The couple had visited the Royal Botanic Garden at Kew on their honeymoon and thought a similar park and conservatory should be built for New York City. The NYBG and the Conservatory were the result.
 
The conservatory was designed by the major greenhouse company of the time, Lord and Burnham Co. The design was modeled after the Palm House at the Royal Botanic Garden and Joseph Paxton’s Crystal Palace in Italian Renaissance style. Groundbreaking took place on January 3, 1899 and construction was completed in 1902 at a cost of $177,000. The building was constructed by John R. Sheehan under contract for the New York City Department of Parks. Since the original construction, major renovations took place in 1935, 1950, 1978, and 1993.
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It is considered a crown jewel of New York City and is a New York City landmark.
     
Google Books
Beyond Intuition:
A Guide to Writing and Editing Magazine Non-Fiction
By Patricia Tichenor Westfall
New York, NY: Longman
1994
Pg. 167:
Ask her what was involved in restoring the New York Botanical Garden’s crown jewel, its Victorian “crystal palace” conservatory, and she won’t tell you about the meetings she attended.
 
Google Books
New York’s 50 Best:
Places to Go Birding in and Around the Big Apple
By John Thaxton
New York, NY: City & Co.
1998
Pg. 18:
The crown jewel of the Bronx, the New York Botanical Garden consists of 250 acres of horticultural wonders, including a 40-acre stand of virgin forest, the oldest and purest in the East.
     
NYC Nature News (2009)
New York Botanical Garden
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Considered a crown jewel of the Bronx, New York Botanical Garden’s accolades go far beyond its home borough to receive praise around the city and in the public gardens world.  With 250 acres, NYBG is a fine location to enjoy local flora and fauna.
   
Daily News (New York, NY)
At New York Botanical Garden’s Holiday Train Show, season’s magic awakens writer’s grandson to wonder
Live action proves more appealing than video games
By Patrice O’Shaughnessy
Wednesday, January 11, 2012, 8:58 PM
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Then, it was on to the Holiday Train Show, erected in the Enid Haupt Conservatory, the crown jewel of the garden.
 
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regularmike‏
@regularmike  
Central Park is not New York’s crown jewel. The New York Botanical Garden in the Bronx blows it away.
6:45 AM - 22 Apr 13