This is part 29 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
This is a diagramless crossword. The clues are not numbered according to their placement in the grid – rather, they are listed so that their answers are in alphabetical order. You must solve the clues and place all answers in the grid, using bolded lines to separate words where necessary. Every cell must be used and grid lines must be rotationally symmetrical. For example, if there is a line separating cells 1–2 on row 1, there must also be a line separating cells 10–11 on row 9.
Whenever one or more letters from the start of the clue form a substring of the answer, those letters must be highlighted in the grid. For example, if the clue starts “On Tuesday...” and the answer is MONTAGE, highlight the letters ONT of the answer in the grid. Or, if the clue starts "Without..." and the answer is SHOWER, highlight the letter W of the answer in the grid. If multiple substrings are possible, highlight the longest one.
Today I have enjoyed the tropical rhythms and landscapes of a large agricultural area surrounded by mountains on all sides. I have visited traditional tobacco plantations and seen massive stalagmites and stalactites that have developed over millennia in the caverns here. Can you guess where I am?
1. Assistant gets real dull (4)
2. Bavarian wheels last bit of riches away from Mohammed bin Salman? (4)
3. Players of baseball gathered around, by agreement in Puerto Rico, to be ones providing childcare (11)
4. Leaving out final part of payment? Two guys on an excellent adventure to get sent an invoice (6)
5. County Tyrone councillors at last appearing before Congress (5)
6. Babushka maybe taken aback having been interrupted by a noisy brawl (6)
7. Babushka's in possession of bananas (4)
8. Beau beheaded again (4)
9. True king switched hands (4)
10. Gradually passes through spot in front of PlayStation (5)
11. Set off to attack king poorly (4)
12. Done in several locations along islands' northern sides (5)
13. Leader in senate conducted vehicle running on surface – that might be a slippery slope (4)
14. Castor & Pollux maybe includes a prominent role by... (5)
15. ...Vincent, appearing in pro performance after one in France that's very demanding (11)
16. Verdi disembowelled in front of lady I saw in Rome (4)
1. What Adam lost behind Charlie's bed (4)
2. Milk product whose designation of origin is protected from terrible fate (4)
3. A leading Italian to make fun of cheap supermarket south of Georgia (9)
4. Bug jeweller finally to cut diamond? (4)
5. Bury a group of players in Italy (5)
6. Homo sapiens is above T-rex, ultimately being without tail (4)
7. Shortage of MDMA in Flanders (4)
8. Rising star hugs former Bond (5)
9. Y'all confused after reworking of topic in a visual fashion? (9)
10. Quick, sharp blow after second round (4)
11. Member of orchestra, just a bit injured, isn't disfigured after violence stops halfway (9)
Gladys will return in Tropical Rhythms (Slight Return).