Don't Look Down!!

Original Link
Posted on 11 June 2015
==Puzzle==
This Challenge will test your memory:
On Tuesday, 14 July 2015, the image was updated to:
Hint 1
If you "Don't look down" then you gotta look up!
Hint 2
Do the math to get a series of running totals. Separate the digits of each result.
Solution
1. Think about what is or was above the tunnels named in each of the weekday answers to fill in the blanks:
 Channel Tunnel - English Channel
 Large Hadron Collider - CERN
 Tom Dick & Harry - Stalg Luft III
 City Hall Loop - New York
 Zerostrasse - PULA
2. Then look at the numbers:
 18 + 5 + 21 + 7 - 19 + 13 + 6 - 6 - 22 + 8 - 16 + 3 + 27 + 7 - 36
3. Do the math to get a series of running totals:
 18, 23, 44, 51, 32, 45, 51, 45, 23, 31, 15, 18, 45, 52, 16
4. Separate the digits of each result:
 1-8, 2-3, 4-4, 5-1, 3-2, 4-5, 5-1, 4-5, 2-3, 3-1, 1-5, 1-8, 4-5, 5-2, 1-6
5. Use the second digit of each pair to index a character in the row on the blackboard indicated by the first digit of the pair. This results in:
CRYPTOPORSICOUS
However, stl.la/cryptoporsicous does not work,
6. Try a Google search, which gives us a corrected spelling:
CRYPTOPORTICUS
which is a tunnel that supports something above it. However, stl.la/cryptoporticus does not work either,
7. It takes a bit of research, but you'll find there is one Cryptoporticus that is sometimes spelled slightly differently than the rest, namely:
ARLES'S CRYPTOPORTICOUS, also known as:
THE CRYPTOPORTICOUS OF ARLES
That seems to go along with this week's theme of specific tunnel names. But neither stl.la/arlesscryptoportiocous nor stl.la/cryptoporticousofarles works.
8. Trying different variations of those, we discover the solution is just part of the name for Arles's Cryptoporticous: stl.la/cryptoporticous
Revision 1
2. Looking at the numbers:
 18 + 5 + 21 + 7 - 19 + 13 + 6 - 6 - 22 + 9 - 16 + 3 + 27 + 7 - 36
3. Do the math to get a series of running totals:
 18, 23, 44, 51, 32, 45, 51, 45, 23, 32, 16, 19, 46, 53, 17
4. Separate the digits of each result:
 1-8, 2-3, 4-4, 5-1, 3-2, 4-5, 5-1, 4-5, 2-3, 3-2, 1-6, 1-9, 4-6, 5-3, 1-7
5. Use the second digit of each pair to index a character in the row on the blackboard indicated by the first digit of the pair. This results in:
CRYPTOPORTSHRLH
However, stl.la/cryptoportshrlh does not work,
==Reward==
Cryptoporticous