Historic Topos: USGS topographic maps from 1879 to 2006. Check Historic Topos and use the year slider and scale box to pick an edition.
Historic aerial imagery: check Historic ESRI aerials, then use the timeline at the top of the map to step back through past photos, back to 2014 and earlier in many areas.
Faster LIDAR loading: LIDAR now loads with fewer, larger tiles and automatically retries tiles that fail.
Second LIDAR source: new ESRI LIDAR option. It loads quickly at any time, with slightly softer detail when zoomed all the way in.
Magnetic Anomaly layer fixed: the USGS server it used went offline, so it now loads from another USGS source.
Note: USGS throttles its LIDAR service at night and on weekends
