There are several Challenge Caches that require you to find the oldest cache in a certain number of countries, hopefully this list will be useful in your quest. We will try and keep the list up to date.
Scotland GCF0 Scotland’s First Traditional 15.12.2000
England GC171 View from Coombe Hill Traditional 14.1.2001
Wales GC2BA First in Wales Traditional 17.2.2001
Northern Ireland GC38D7 pussycat Traditional 10.2.2002
Aland Isles GCGW3M Aland Traditional 1.8.2003
Albania GC17X8V Shqiperia Earthcache #1 – Former river-channel Earthcache 8.8.2007
Andorra GC42E3 Casamanya Traditional 16.3.2002
Antigua and Barbuda GC5D78 Lookout Point Virtual 8.5.2002
Aruba GC5A9A Wish Rock Garden Traditional 17.5.2002
AustraliaGC3E Lane Cove Virtual 18.5.2000
Austria GC1298 Salzig Hund Traditional 23.7.2001
Azerbaijan GC16BJJ Mud Volcano Cache Traditional 30.9.2007
Bahamas GCC411 The Caves Traditional 13.1.2003
Bahrain GCP4ZC The Tree of Life Traditional 1.6.2005
Bangladesh GC2MYW8 DUTCH POINT DHAKA Traditional 26.1.2011
Barbados GCA952 The Barbados Museum Virtual 14.11.2002
Belarus GC1V5WY The Second in Belarus 24.6.2009
Belgium GC40 Geocache Traditional 7.7.2000
Belize GC15D Oh so blue Traditional 6.1.2001
Benin GC1N8B0 Abomey Royal Traditional 14.1.2009
Bhutan GC20P0Z Tang Treasure Traditional 17.10.2009
Bolivia GCG8Q4 Cristo de la Concordia Cache Virtual 4.6.2003
Bosnia and Herzegovina GCJVHV Bukovic Mountain #1 Traditional 12.6.2004
Botswana GCGYHZ Aardvark Virtual 23.9.2003
Brazil GCC67 Mission 4: Southern Bowl Ape 14.6.2001
British Indian Ocean Territory GCK6A1 Diego Garcia B.I.O.T. Traditional 4.8.2004
British Virgin Islands GC4876 Eyrie Virtual 2.4.2002
Brunei GC1H7VK Mar-Cat Traditional 12.10.2008
Bulgaria GCB088 The Orpheus Cache Traditional 30.11.2002
Burkina Faso GC1M1N7 Parc W – Kabougou Traditional 7.1.2009
Burma/Myanmar GCFA5A Mingalazedi View (Myanmar/Burma) Virtual 6.4.2003
Cambodia GC21N8D Phnom Kulen National Park Earthcache 28.10.2009
Cameroon GCGH6Q Wasa Park Virtual 26.3.2003
Canada GCBBA Geocache—Canada’s 1st geocache Traditional 28.6.2000
Cayman Islands GC2978 TO HELL AND BACK Virtual 22.11.2001
Central African Republic GC5XGE4 Bangui la coquette – M’poko le foyer du soldat 14.6.2015
Chad GC1REHX GO TCHAD GO Traditional 13.5.2009
Chile GC3FCD Araucaria in Conguillio Traditional 27.2.2002
China GC201F Berry Virtual Cache Virtual 2.10.2001
Christmas Island GC1TAXW The Christmas Train 5.6.2009
Colombia GC15VAG El futbolista Carrasposo / The “carrasposo” Soccer 8.9.2007
Cook Islands GC1NEQ4 Rarotonga Cook Islands – Canuck Cache 10.2.2009
Costa Rica GC6CCA Christopher Columbus’s 4th and Final Voyage Virtual 14.6.2002
Croatia GC2499 Saint Ivan Traditional 25.10.2001
Cuba GC5B6F Cuba Libre Traditional 18.5.2002
Curaçao GCKT6P Pittig Ding Traditional 11.10.2004
Cyprus GC926F The first traditional in Cyprus Traditional 21.9.2002 18.8.2001
Czechia GCE50 Tex-Czech Traditional 1.6.2001
Denmark GC6A Kippers in the Jungle (Denmark’s first) Traditional 20.9.2000
Djibouti GCPAFJ Lac Assal, Really Deep 14.6.2005
Dominica GC1T0RW Emerald Pool Earthcache 29.5.2009
Dominican Republic GCG1CM A walk in the Park Virtual 21.4.2003
Ecuador GC934A The Fake Equator Virtual 25.9.2002
Estonia GC263 HE-stash / HE-aare Traditional 10.2.2001
Eritrea GCRCNC Dur Ghella Cache Traditional 19.11.2005
Ethiopia GCB5D7 Erta Ale Volcano Traditional 6.12.2002
Falkland Islands GC17CXT Falkland Islands 2nd Albermarle Harbour 14.11.2007
Faroe Islands GCMPFC Skansin Traditional 5.2.2005
Fiji GC7590 Malololailai 20.7.2002
Finland GC72 Sun Gear Traditional 30.9.2000 (Premium Member)
France GC7A2 La Vigie Traditional 22.4.2001
French Guiana GC2WC1G Savane-roche Virginie Earthcache 16.5.2011
French Polynesia GCG9B6 Hidden Tahiti Treasure Virtual 11.6.2003
French Southern and Antarctic Territories GC51G4H L’une des caches les plus isolées du monde Traditional 1.4.2014
Gabon GC2D6HR Cookie Tin Traditional 7.8.2010
Georgia GCV3AH Georgia on my mind Traditional 27.3.2006
Germany GC26C Medieval View Traditional 11.2.2001 (Premium Member)
Ghana GCH6Z7 Baboon Country Traditional 9.11.2003
Gibraltar GCA227 1st Gibraltar Traditional 28.10.2002
Greece GC1B5B Agia Irene Traditional 18.8.2001
Greenland GC8074 El Conquistador’s Treasure Traditional 11.8.2002
Grenada GCGGQX What a Hole Virtual 23.7.2003
Guadeloupe GCR847 Castle cache Traditional 6.11.2005
Guam GC357C Two lovers point Virtual 26.1.2002
Guatemala GC2A86 Tikal Traditional 27.11.2001
Guernsey GC3209 View.1 Traditional 13.1.2002
Guinea GC4H7R6 The first cache in Guinee: Le Dauphin 27.7.2013
Guinea-Bissau GC57XD4 Lugajole Traditional 22.6.2014
Guyana GC206AP Kaieteur Falls Earthcache 23.10.2009
Haiti GC8D0 Cruise Cache – Labadee Beach Traditional 1.5.2001
Hong Kong GC251B Lantau Virtual 21.10.2001
Hungary GCD68 FakeCastle 24.6.2001
Iceland GC7AD7 Karin Near Kistufell Traditional 5.8.2002
Indonesia GC1488 Indonesia One – Bali Traditional 24.7.2001
Ireland GC43 Europe’s First Traditional 3.6.2000
Isle of Man GC5A4C Manx Traditional 20.5.2002
Italy GC17B3 Bergwind Traditional 15.5.2001
Japan GC268C Oku Hamanako Traditional 14.11.2001
Jersey GCB662 Jersey number One Traditional 15.12.2002
Kenya GC53 Rift Valley Virtual 15.6.2000
Latvia GC1J94K Trebas 3 litru burka Traditional 14.6.2003
Liechtenstein GCC2F4 Liechtenstein’s First Traditional 12.1.2003
Lithuania GCGCMZ Tulip time Traditional 12.5.2033
Luxembourg GC4871 Grand Luxembourg Quest I (virtual part) 2.4.2002
Macedonia GCB82C Tupolev 154 Traditional 23.12.2003
Malta GCHEQ7 The Ring of Clapham Junction Traditional 4.1.2004
Malaysia GC9FDB Welcome to KL Virtual 24.10.2002
Mauritius GCH02Z Garden Treasure Traditional 22.9.2003
Mexico GC6CB Viva Baja #2 Traditional 12.4.2001
Moldova GCT1QN First Cache in Moldova Traditional 16.1.2006
Monaco GC2DC2 top of monaco Traditional 24.12.2001
Montenegro GC1095F Dome View 4.1.2007
Netherlands GC198 Amsterdam Urban 1 Traditional 21.1.2001
New Zealand GC46 Geocache by Kevin Anderson (Wellington) Traditional 26.5.2000
Norway GCBBF Norges første, I Bergen, The first cache in Norway Multi 9.6.2001
Poland GC26A9 Ndebele Virtual 1.11.2001
Portugal GC8EF9 AZGTJ – Translant Chess Cache Traditional 15.5.2001
Romania GC5D8 Dracula’s Castle Traditional 1.4.2001
Russia GC162E Mutnovsky:1 (Nikolay Kam:2) Traditional 12.8.2001
San Marino GCNTKF [BAU] San Marino #1 Traditional 5.5.2005
Slovakia GCKRD6 Mokre nohy (Wet Legs) Mystery 6.7.2001
Slovenia GC103E Prvi Geocache v Sloveniji Traditional 29.6.2001
South Africa GC185 Sentinel View Traditional 18.1.2001
Spain GC2D4 Montserrat 18.2.2001
Sweden GC4D Match Stash Traditional 11.8.2000
Switzerland GC2A5 Gstaash Traditional 27.1.2001
Ukraine GC11WCJ Verecke pass (GC896 – Honglalás) Traditional 25.7.2005
USA GC30 Mingo Traditional 11.5.2000
Venezuela GCE64 Arekuna Traditional 20.6.2001