knowledge - Gladys unchained

_{This puzzle is part 2 of Gladys' journey across the globe. If you're new to the series, feel free to start at the beginning: Introducing Gladys.}

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Dear Puzzling,

Today I spent the entire day outdoors. There are so many enjoyable parks and gardens in this area. Who says you can't enjoy nature in a big city? The puzzle I'm sending you is a word chain. The name of my destination consists of two words. Have fun!

Wish you were here!
Love, Gladys.

1. A pope essentially munched alongside me during a period of fasting (7)
2. American car's air conditioning is beyond breaking point (7)

3. Black Prince, extremely exhausted, abruptly draws back (6)
4. Fantastic Potter has Elizabeth I's crown (7)
5. Football club's anthem botched by small child (9)
6. For every leading actor group, a prediction (8)
7. Half of meal prepared before specified time (7)
8. Make up a guess about jolly couple's birds (8)
9. Minister's corrupt circle (6)
10. Permanent building (6)
11. Prominent Republican host with a murderous brother (6)
12. Real corruption in Karnataka's bordering state (6)

13. Saloon outside Kazan's central marketplace (6)
14. Senseless gun mob regularly after central banks (4)
15. Short person essential to hybrid warfare (5)
16. Superman, finally social, upset Kal-El's dad (7)
17. Untalented writer has trouble finishing diacritical mark (5)
18. Vegetable food course by sun god (6)

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_{Gladys will return in "T-Rex goes cooking".}

Answer

Gladys is in the

https://en.wikipedia.org/wiki/Emerald_Necklace.

Clues and solutions:

CLEMENT    1. A pope essentially munched alongside me during a period of fasting (7)
PONTIAC    2. American car's air conditioning is beyond breaking point (7)
EDWARD     3. Black Prince, extremely exhausted, abruptly draws back (6)
TREETOP    4. Fantastic Potter has Elizabeth I's crown (7)

TOTTENHAM  5. Football club's anthem botched by small child (9)
FORECAST   6. For every leading actor group, a prediction (8)
ALREADY    7. Half of meal prepared before specified time (7)
SEAGULLS   8. Make up a guess about jolly couple's birds (8)
CLERIC     9. Minister's corrupt circle (6)
STABLE    10. Permanent building (6)
MCCAIN    11. Prominent Republican host with a murderous brother (6)
KERALA    12. Real corruption in Karnataka's bordering state (6)
BAZAAR    13. Saloon outside Kazan's central marketplace (6)
NUMB      14. Senseless gun mob regularly after central banks (4)

DWARF     15. Short person essential to hybrid warfare (5)
NICOLAS   16. Superman, finally social, upset Kal-El's dad (7)
HACEK     17. Untalented writer has trouble finishing diacritical mark (5)
RADISH    18. Vegetable food course by sun god (6)

Many of these were also solved by @hexomino, but I haven't looked at their answers ... except that I wasn't able to figure out #10 and peeked at that one, which apparently was actually solved by Chris Cudmore in comments. Kudos to Chris!

Piecing these together we get:

  A C E R O F R A W D
  S N E T T O T N E R
  T H A H S I D A M A

  R A C Y D A E R E W
  E M E . . . R A L D <--
N E C K . . . L A C E <--
I T C E R A L A Z I L
C O A I N U M B A R B
O P O N T I A C L E A
L A S E A G U L L S T

There is one thing I don't understand:

the definition part of #16. The wordplay is clear enough, but the definition has to be "Kal-El's dad" and I am failing to see why that should be NICOLAS rather than either JOR-EL or JONATHAN. [EDITED to add:] Thanks to El-Guest for setting me straight on this one. It turns out that Nicolas Cage actually named his son Kal-El. Gosh.