JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.5.1/leaflet.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/leaflet/1.5.1/leaflet.css">
<div id="map">

</div>

CSS

#map{
  width:100%;
  height:300px
}

.popup {
 text-align:center;
 }
  .popup .slideshow .image        { display:none; }
  .popup .slideshow .image.active { display:block; }
  .popup .slideshow img {
 width:100%;
 }
  .popup .slideshow .caption {
background:#eee;
 padding:10px;
 }
  .popup .cycle {
 padding:10px 0 20px;
 }
 .popup .cycle a.prev { float:left; }
 .popup .cycle a.next { float:right; }

JavaScript

var geoJson = {
"type": "FeatureCollection",
      features: [{
      type: 'Feature',
      "geometry": { "type": "Point", "coordinates": [-122.11587572202124, 42.937756819243909]},
      "properties": {
          'title': 'Washington, D.C.',
          'images': [
            ['http://freakplaces.com/img/Cannon_Beach17.jpg','The U.S. Capitol after the burning of Washington during the War of 1812'],
            ['https://i.imgur.com/xND1MND.jpg','Ford\'s Theatre in the 19th century, site of the 1865 assassination of President Lincoln'],
            ['https://i.imgur.com/EKJmqui.jpg','The National Cherry Blossom Festival is celebrated around the city each spring.']
          ]
      }
  }, {
      type: 'Feature',
      "geometry": { "type": "Point", "coordinates": [-123.97288585689788, 45.903886579968066]},
      "properties": {
          'title': 'New York City',
          'images': [
            ['http://freakplaces.com/img/Cannon_Beach17.jpg','Peter Minuit is credited with the purchase of the island of Manhattan in 1626.'],
            ['http://freakplaces.com/img/CraterLakeNP14.jpg','During the mid-19th Century, Broadway was extended the length of Manhattan.'],
            ['https://i.imgur.com/Pk3DYH1.jpg','Times Square has the highest annual attendance rate of any tourist attraction in the world.']
          ]

      }
  }]};


var map = L.map('map').setView([51.505, -0.09], 0);

 L.geoJson(geoJson, {
onEachFeature: onEachFeature
}
  ).addTo(map);


   function onEachFeature(feature, layer) {
// does this feature have a property named popupContent?
if (feature.properties && feature.properties.title) {

    var images = feature.properties.images
    var slideshowContent = '';

    for(var i = 0; i < images.length; i++) {
        var img = images[i];

        slideshowContent += '<div class="image' + (i === 0 ? ' active' : '') + '">' +
                              '<img src="' + img[0] + '" />' +
                              '<div class="caption">' + img[1]...