Day 9: Morning balloon launch, Ihlara Valley hike, Derinkuyu underground city, and Uçhisar Castle
by Steve, Katherine, and Norah
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Underground Palace -Cistern Water System
by Huiqing
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Seattle Underground Tour
by Jeff B.
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Pendleton Underground Tour
by Jeff B.
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Montreal Underground
by Guy Dube
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Port Angeles Underground
by Jeff B.
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City of Kaymakli
by Denise J T Lee
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Ho Chi Minh City (Cu Chi Tunnels), Vietnam (December 2008)
by taboo5
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In the city
by Dave Witten
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HO CHI MINH CITY (SAIGON)
by JerryE
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