Show conferences when "Country" is clicked is not working properly - php

Question

I have a modal that has some cities. If the user clicks in a city then in the #conferences div it appears the conferences that have in the column "city" that clicked city. This is working fine.
My doubt is how to, if the user clicks in Country, instead of a city, how to get all conferences, independently of the city because if the user click in Country the results can be of any city.
Do you know how to achieve that?
With value attribute like "" "<a value="">Country</a>" when "Country" is clicked in the console appears:
" {message: "", "exception: "Symfony\Component\HttpKernel\Exception\NotFoundHttpException",…}" in file "/Illuminate/Routing/RouteCollection.php".
ConferenceController method to get the conferences of the clicked city:
public function getConferencesOfCity($slug)
{
$conferences = Conference::whereCity($slug)->get();
return response()->json($conferences);
}
Modal where the city links appears:
<div class="modal-body">
<div class="container">
<ul class="modal-list row">
<li class="col-lg-4 col-md-6 col-sm-12">
<a class="" name="" id="" value="">Country</a>
</li>
#foreach($cities as $city)
<li class="col-lg-4 col-md-6 col-sm-12">
<a class="" name="city" id="{{$city}}">{{$city}}</a>
</li>
#endforeach
</ul>
</div>
</div>
Route:
Route::get('conferences/where/city/{slug}','ConferenceController#getConferencesOfCity')->name('city.conferences');
jQuery ajax request:
$("a[name='city']").on('click', function(){
$('#showCities').html($(this).text());
var city = $(this).attr("id");
$.ajax({
url: '{{ route('city.conferences',null) }}/' + city,
type: 'GET',
success:function(result){
console.log(result)
$('#conferences').empty();
var newConferences='';
var placeholder = "{{route('conferences.show', ['id' => '1', 'slug' => 'demo-slug'])}}";
$.each(result, function(index, conference) {
$('#modal2').modal('hide');
var url = placeholder.replace(1, conference.id).replace('demo-slug', conference.slug);
newConferences += '<div class="col-12 col-sm-6 col-lg-4 col-xl-3 mb-4">\n' +
' <h5 class="card-title">'+conference.name+'</h5>\n' +
<p class="card-text font-size-sm">'+conference.city+'</p>\n' +
' </div>\n';
});
$('#conferences').html(newConferences);
},
error: function(error) {
console.log(error.status)
}
});
});