It's about 2,000,000 times as big as Alcatraz
In other words, 16,963,860 hectares is 1,900,000 times the size of Alcatraz, and the size of Alcatraz is 0.000000530 times that amount.(a.k.a. The Rock) (California)
Alcatraz Island measures 8.90 hectares. It is known a part of the Golden Gate National Recreation Area, and has historically served as a lighthouse, fort, military prison, and — most famously — a federal prison.
It's about 2,000,000 times as big as Buckingham Palace
In other words, 16,963,860 hectares is 2,200,000 times the size of Buckingham Palace, and the size of Buckingham Palace is 0.000000450 times that amount.(a.k.a. Buckingham House) (Westminster, London, England)
Buckingham Palace, the official residence of the British monarch, contains about 7.70 hectares of total floor space. The palace was first inhabited by Queen Victoria in 1831, although after the death of her husband in 1861, the Queen endeavored to spend as little time there as public opinion would allow.
It's about 2,500,000 times as big as Croke Park
In other words, the size of Croke Park is 0.000000380 times 16,963,860 hectares.(a.k.a. Páirc an Chrócaigh) (Dublin, Leinster, Ireland) (stadium area)
Croke Park, the Gaelic games stadium of Dublin, hosts hurling and Gaelic football matches in a 6.50 hectares stadium. The Park offers rooftop tours, where fans can walk along the 44-meters-high walkway.
It's about 3,000,000 times as big as Windsor Castle
In other words, 16,963,860 hectares is 3,200,000 times the size of Windsor Castle, and the size of Windsor Castle is 0.000000310 times that amount.(Windsor, England) (total site area)
One of the official residences of the British monarch, Windsor Castle measures about 5.30 hectares. It is the largest inhabited castle in the world and is also the oldest in continuous use, having been occupied since it was built by William the Conqueror about 900 years ago.
It's about 3,500,000 times as big as Rogers Centre
In other words, the size of Rogers Centre is 0.0000003030 times 16,963,860 hectares.(f.k.a. Skydome) (Toronto, Ontario, Canada) (entire complex)
Rogers Centre, a major sports stadium in downtown Toronto, measures a total of 5.140 hectares over the entire complex. The video board of Rogers Centre has a total area of 0.034 hectares.
It's about 3,500,000 times as big as a Polo field
In other words, 16,963,860 hectares is 3,381,434.620 times the size of a Polo field, and the size of a Polo field is 0.0000002957324660 times that amount.(for field polo) (United States Polo Association rules; unboarded side maximum)
An outdoor polo field must measure 274.32 m in length and 146.304 m to in width for a total playing area of up to 5.01676416 hectares. Polo traces its origins to an Iranian (then Persian) war game from the 5th Century, which was played with as many as 100 players per side.
It's about 4,000,000 times as big as The Principality Stadium
In other words, the size of The Principality Stadium is 0.000000300 times 16,963,860 hectares.(a.k.a. Stadiwm Principality, f.k.a. Millennium Stadium, f.k.a. Stadiwm y Mileniwm) (Cardiff, Wales, United Kingdom) (total footprint)
The 70,000-person-plus capacity stadium of Cardiff, Principality Stadium has a total footprint of 4 hectares. Over 40,000 tonnes of concrete and steel during the construction of the stadium.