bridges and tunnels...

http://www.notey.com/@vancitybuzz_unofficial/external/4844085/on-this-day-ironworkers-memorial-bridge-collapsed-57-years-ago.html

https://pricetags.wordpress.com/2016/08/26/first-rule-for-a-third-crossing/

http://journalofcommerce.com/Infrastructure/News/2015/11/Plans-for-new-water-supply-tunnel-underway-1011542W/

http://www.soundernews.com/lifestyle/bridges-over-troubled-waters.html


https://en.wikipedia.org/wiki/Grand_Central_Terminal#Layout

https://en.wikipedia.org/wiki/Pennsylvania_Station_(New_York_City)#History