[Chain of puzzles - ended] Castles, sights and other [+solution]

im stuck in 3 puzzle Q4 :( does not give me exact year

Proud bump for solved! :D Nice set of puzzles.

First puzzle was very nice although it is lost time for me since I already have the game... Don't have enough Contribution value for other giveaways so didn't even check other puzzles. Thanks for them!
Good luck to others!

great puzzle, I've done with first and second step. Now 3 step is waiting for me :)

Bumping for solved, just waiting to see what's up now.

I am stuck on q4 in math part.... I think I have a right number, but still only "wrong" :(
I think I dont understand a question right..

I can't get Quiz 2, question 3. I KNOW I have the right building, and I've tried at least thirty variations of the name. You said in an earlier post that the names come from the English wikipedia, and I've tried everything from there and then some. Can I please have a hint about what you could possibly be asking for?

Bump, awaiting hints for the third step :)

bump solved! Thanks! really hard puzzle (especially 3rd step):)

Solved first two, they were nice and easy. I have some concerns about the precision in step 3 tho.

Where's second puzzle?

Damn, I was hoping for an hint on q4 :(

The giveaway of step 1 is complete. Congratulations to the winner. =)
Two more steps are still available.

HUGE BUMP, solved last step! :D

Two hours left to solve the puzzle for giveaway of 2nd step in time.

The giveaway of step 2 is complete. Congratulations to the winner. =)
Last step is still available.

Less than two hours left to solve the puzzle for last giveaway. Hurry up! ^_^

Well, puzzle finished.
Congratulations to the winner of last step and thanks to all for participating! ^_^
Answers are present below.

Answers for Step-1

All pictures were reverse-searchable.

1. Aït Benhaddou
2. Krak des Chevaliers
3. Aragonese Castle
4. Bodrum Castle
5. Palace of the Grand Master of the Knights of Rhodes
6. Windsor Castle
7. Manzanares el Real
8. Ivangorod
9. Château de Tarascon
10. Kost Castle
11. Mir Castle Complex
12. Himeji Castle
13. Reichsburg Cochem

Only Q9 and Q13 are absent in the English Wikipedia (but still searchable), it’s why simple answers like Tarascon and even Reichsburg were allowed too.

Giveaway was Adventures of Shuggy.

Answers for Step-2

The well-known sights were used here (though with some tricks =P). This stage has been especially easy if you've played Civilization.

1. Eiffel Tower
2. Sydney Opera House
3. Moscow Kremlin
4. Angkor Wat
5. Statue of Liberty
6. Brandenburg Gate
7. St. Peter's Basilica
8. The Louvre
9. Golden Gate Bridge
10. Sagrada Família
11. Sultan Ahmed Mosque
12. Saint Basil's Cathedral
13. Leaning Tower of Pisa
14. Great Wall of China
15. Christ the Redeemer
16. Great Pyramid of Giza
17. Big Ben
18. Taj Mahal
19. Colosseum
20. Burj Khalifa

Giveaway was Tropico 4.

Answers for Step-3

This puzzle was at attention, logic and math skills.

1. Obviously to calculate weight you needed to know a volume of the bottle here. It was in the text though: fifth. Then you needed to use the density of the gold (it’s various in the different sources; that’s why I told rely on English Wiki and also added that value in the hint):
757 * 19.3 = 14610.1 g
Answer: 14.61 (in kg, with only 2 decimal digits as it was noted in the topic of 2nd giveaway).

2. There was a possible pitfall. The gold price is usually given for 1 ounce and it is not usual ounce of 28g, but troy one. Although you could easily avoid this pitfall when using the price from the Wikipedia article about gold (the price for kilogram is there as well).
Anyway income is:
(14.61 / 0.0311034768) • $20.67 = $9709.16
or
14.61 • $664.56 = $9709.22
Jack spent 8000+20+9+200+(all change) = $8229 and all cents.
So he put into the account 9709-8229 = 1480 dollars.

3. It’s easy task about compound interest.
Future Value = Present Value • (1 + i)^n = 1480 • (1 + 0.04)^200 = 3775109.69

4. Last step was tricky a bit, because no special formula exist for inflation. So it required some logic here:
first annual fee = $1000
2nd = $1000 • 1.02
3rd = ($1000 • 1.02) • 1.02 = $1000 • 1.02^2
Obviously it’s geometric progression!
You needed to find period when sum of progression will be equal to Marty’s money:
S(n) is known = 3775109.69 – 150000 = 3625109.69
r is known too = 1.02
Expressing n from this formula you will receive ~217.00733
Answer is 217

Giveaway was Recettear: An Item Shop's Tale.
BTW, if someone was unlucky but wish this game, it’s under sale on Steam currently: clicky.

Yeah!! My first win in steamgifts! Thank you very much GrayFiend! The puzzles were great!