52.0.0.0/10

ip:	52.0.0.0 ec2-52-0-0-0.compute-1.amazonaws.com
loc:	United States, Ashburn (Virginia)  
isp:	AS14618 Amazon.com, Inc. » Amazon.com, Inc. » AWS EC2 (us-east-1) 1.136 ms
route:	52.0.0.0/10, AT-88-Z - Amazon Technologies Inc., US (Ashburn) ... 
reg:	52.0.0.0/10, US, ARIN, 1991-12-19
addr:	  410 Terry Ave N. Seattle WA 98109 US
online:	  313.070 » latency: 122 ms (200ms) 

see also:
   52.0.0.0/11      AS16509  AT-88-Z Amazon Technologies Inc., US
   52.0.0.0/15      AS14618  AT-88-Z Amazon Technologies Inc., US
   52.2.0.0/15      AS14618  AT-88-Z Amazon Technologies Inc., US
   52.4.0.0/14      AS14618  AT-88-Z Amazon Technologies Inc., US
   52.8.0.0/16      AS16509  AT-88-Z Amazon Technologies Inc., US
   52.9.0.0/16      AS16509  AT-88-Z Amazon Technologies Inc., US
   52.10.0.0/15     AS16509  AT-88-Z Amazon Technologies Inc., US
   52.12.0.0/15     AS16509  AT-88-Z Amazon Technologies Inc., US
   52.14.0.0/16     AS16509  AT-88-Z Amazon Technologies Inc., US
   52.15.0.0/19     AS16509  AT-88-Z Amazon Technologies Inc., US
   52.15.32.0/19    AS16509  AT-88-Z Amazon Technologies Inc., US
   52.15.64.0/18    AS16509  AT-88-Z Amazon Technologies Inc., US
   52.15.128.0/17   AS16509  AT-88-Z Amazon Technologies Inc., US
   52.16.0.0/15     AS16509  AMAZON-DUB Amazon Data Services Ireland Limited, IE
   52.18.0.0/15     AS16509  AMAZON-DUB Amazon Data Services Ireland Limited, IE
   52.20.0.0/14     AS14618  AT-88-Z Amazon Technologies Inc., US
   52.24.0.0/14     AS16509  AT-88-Z Amazon Technologies Inc., US
   52.28.0.0/16     AS16509  AMAZO-ZFRA A100 ROW GmbH, DE
   52.29.0.0/16     AS16509  AMAZO-ZFRA A100 ROW GmbH, DE