Each of the puzzles below gives a two-word answer. Solve the puzzles and arrange the resulting 16 words into four groups of four, each with a common theme. The resulting group names form a clue for the final answer.

• I did wonder what was going on. Mar 29, 2019 at 13:49
• Ooohh, it all makes sense now! :D Mar 29, 2019 at 13:50
• Each puzzle is a stand alone, so I'm ok with it. Mar 29, 2019 at 16:59
• @North I see what you mean. I thought about posting one big puzzle, but navigating the partials would have gotten confusing pretty fast... There's already a wiki answer below listing the solutions so far.
– Jafe
Mar 29, 2019 at 17:08
• I like it @jafe. Well done. Mar 29, 2019 at 17:20

The four groups are:

1

London: Fire, Marathon, Olympics, Underground

2

Tower: Cell, Devils, Ivory, Water

3

Guard: Coast, National, Old, Security - thanks @arbitrahj for this one

4

Duty: Cycle, Double, Heavy, Line

London Tower Guard Duty, which seems to be hinting at the Yeomen Warders, whose duty it is to guard the Tower of London.

• This is the intended answer. Well done!
– Jafe
Mar 30, 2019 at 11:57

1. Written every which way

Ivory Coast

2. A manager's dilemma

Fire Devils

3. Keeping you safe

National Security

4. Coordinated efforts -

Old Olympics

5. Contours of a clandestine nature

Underground Line

6. Between two walls

Cell Cycle

7. Pulling a fast one

Double Marathon

8. In excess I'm lethal

Heavy Water

Some initial guesses:

1.

Life Line, Cycle, Double, Cell.

2.

Guard Old, National, Security, Coast

3.

Medal(metal) Heavy, Devils, underground, olympics

1. ??? Kinda falls apart

red white and blue?? Fire Water, Ivory, marathon

Or

rings fire, olympics, underground, cell

Which moves

Water to life

Leaving

Heavy, devils, ivory, marathon which is still ?????

Possible Groupings [1,2,3,4 contradict with each other, just listing some possible combinations]

1:

Lines/Contours: Coast, Line, Marathon, ?

2:

Sports [unlikely]: Olympics, Marathon, ?, ?

3:

Metal: Devils (devils metal: silver), Heavy (heavy metal), Underground?, ?

4:

Loops: Cycle, Olympics (5 cicles on flag), Underground (System map looks like a loop), ?