Some contenders for hardest to pronounce:
* Ljubljana, Slovenia: The "Lj" sound is difficult for many speakers.
* Kuala Lumpur, Malaysia: The "K" and "L" sounds are often blended together by non-native speakers.
* Yerevan, Armenia: The "Y" and "e" sounds can be challenging.
* Ulaanbaatar, Mongolia: The "U" and "a" sounds can be difficult to distinguish.
* Kathmandu, Nepal: The "th" sound can be tricky for some.
* Wroclaw, Poland: The "W" and "r" sounds combined can be difficult.
* Quito, Ecuador: The "Q" and "u" sounds combined can be difficult for some speakers.
* Reykjavik, Iceland: The "K" and "v" sounds combined can be challenging.
Ultimately, the hardest capital to pronounce is the one you find most challenging!