Bryant Park has all the characteristics of a great Pokemon hotspot. It features a cluster of Pokestops that can all be spun in one place. The park itself has a fair sized nest which has been home to Bulbasuar, Jigglypuff and Mankey in previous migrations. Trainers can loop around the park to restock on items while also hunting for Pokemon that have migrated there. The open lawn in the center of the park is ideal for taking a breather from Pokemon and tossing around a frisbee with friends.
In 1884, Reservoir Square was renamed Bryant Park, to honor William Callen Bryant, romantic poet and newspaper editor. Around the same time, plans were in motion to demolish the old Croton Reservoir adjacent to the park. It would be replaced by the Beaux-Arts building or better known as the central branch of the New York Public Library.
In 1934, the park was redesigned by architect Lusby Simpson. The plan featured a large central lawn, formal pathways and an oval plaza containing the Josephine Shaw Lowell Memorial Fountain. However the park was a common locale for drug trafficking and by 1979, the city seemed to have given up on it as a public amenity. It was in 1980, when Andrew Heiskell and Daniel A. Biederman created a plan for turning the park around. It was a seven year project that brought in revenue and doubled the number of annual visitors. Today, Bryant park attracts six million annual visitors.
I'm better off listing what trains don't stop near Bryant Park.
Bryant park is a park biome that will see an uptick in grass and bug Pokemon. Alongside those is the Pokemon that have taken home in the park during the current migration. Trainers should note the library that is next to the park is not consider part of the park biome. In other words, you're not going to find any nest Pokemon there.
The southern corner of the park near the HBO building is where the cluster of Pokestops are. I'm actually not sure where to comfortably stand to play here. However one option is to play in the subway station if it happens to be a miserable day out. If you pay to get in the subway station near the HBO building, you can play on the benches after the turnstiles. The subway also has a stable WiFi connection to play on. Personally, it's a bit strange to be paying to just sit there. It might be a good idea if you were planning to go somewhere and you are passing some time.
Facing the libary, the Bryant Park bathroom is located on the left towards the back. (The bathroom is quite nice.)
Bryant Park is a solid hotspot to visit to play Pokemon Go and remains a popular loaction for local players. The park itself offers things to do year round including pop-up shops, unique snacks, and a carousel. In addition to the parks's shops, the Kinokuniya bookstore and the Muji flagship store opposite the park are my favorite places to browse when I'm near. Definitely check it out.
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