announcer: coming up onon "21st century"... today we shed light on the service and sacrifice of heroic individuals who deploy from key troop-contributing countries to u.n. peacekeeping operations. their dedication is representative of tens of thousands of blue helmets now serving around the world.

[music playing] [vocalizing] [background crowd chatter]

[peacekeeper speaking spanish]

[famimily cheheing] child: dadaddy! man:n: yes. woman: wowow! yes! [siren] officer: attention! wowoman: present arms! [bugle call]

[crowd cheering] [president-elect george weah speaking]

[singing cadence]

[indistitinct group reply] [whistle blows] [natalia speaking spanish]

[indistinctct chatter]

doctor: i am dr. walid from [indistinct] in malali. you know, in this ararea there e a lot of peoeople in need off very simple medicine. [i[indistinct c conversrsation] [woman speaking local language] interprpreter: cannot eat. sosome fever. drdr. walid: is there a fevever? the problem is...uh, baby? [indistinct chatter]]

[man speaking local language] [man speaking indistinctly] second man: no problem. [ntalouou speaking local langua]

[man speaking] [interprpreter speaeaking] man: i will finish. startrting from here. [indistinct] [all talking at once] [valerie compas speaking french]

[man speaking french] [both men speaking french] [man speaking french] [compas speaking]

deuti gurung: i am superintendndent of police, deui gurungng, and cucurrently y'm me chief of canine squad of nepal.

professionally, i am veterinary doctor, too. i deployed as a u.n. police officer in 2008 in eastst timor. there i worked as the chief of the national operations center. i used to see the u.n. cars with the blue e ates and all and with the blue berets and all. i i always had like the inquisity of how to work in those countries and all with the police serving in the u.n. so i just wanted to like see and experience and serve. that's why i applied and i got through the exams and i went. in 2008 in east timor people were still not healed, you know. their relatives were killed and all. so working with the police, the local police over there and mobilizing the police, the international police, it was a big chchallenge and it was a very sensitive case also, sensitive job for me. so it was quite challenging for me, that job was. we wewere working with the local police also, like we had to

train them. there were, i think. 52 countries, like police people were there. so, in the national operations center where i was working there, like we had like from all the countries. making them all work together smoothly, it was also a different part fofor me. lilike getting along with them and working with the people from the east timor, it was different. i recall the incidentnts, i visualize them ad like how they are suffering and how they are working, the u.n. police helping them outut. and it's a n nice experience for meme that i c can never forget in my lifefe. it gives me immene pleasure, and i'm proud also.

[wilhelm scavo speaking italian]

[michele melis speaking italian] [serena bonifaclo speaking italian]]

[indistinct chatter] [sirens] [zhang ying speaking]

[sirens] [captain gabrhiwot gebru speaking amharic]

[indistinct chatter]

[crowd cheering]

announcer: coming up on a future edition of "21st century"... [souleymane traore speaking bambara language]

[boubakar sidiki samake speaking french] ççagg1ab;ñ;ñ;ñ;ñ;ñ;ñ;ñ;ñ;ñ1ñ1ñs

[dramatic music] ♪ smith: in isis epide of " "world on the brink," we are goingo o look a pararof the world where threcocontints and d ny cultures collide, the origin of the three great monotheistic religions, and the source of many of today's most violent conflicts: the middle east.