Links to places, websites and groups I have found and like.
http://www.crazy-places.com : A friends website. Urbex exploration and Cold War sites. Have visited a couple of these sites, the U-Boat Command Bunker being my favourite.
http://www.aprs2.net : The Tier2 APRS Group.
http://www.mkraynet.org.uk : Milton Keynes RAYNET Group.
https://tracker.habhub.org : APRS Balloon Tracking ( Just because it’s interesting stuff ).
https://globe.adsbexchange.com : The world’s largest co-op of ADS-B/Mode S/MLAT feeders.
https://www.lightningmaps.org : A community project with free real time lightning maps.