diff --git a/src/app.tsx b/src/app.tsx
index 58b65ee..f923e80 100644
--- a/src/app.tsx
+++ b/src/app.tsx
@@ -12,6 +12,7 @@ import {Intro} from './intro';
 import {Loader, Message, Portal, Responsive} from 'semantic-ui-react';
 import {Redirect, Route, RouteComponentProps, Switch} from 'react-router-dom';
 import {TopBar} from './top_bar';
+import {loadWikiTree} from './wikitree';
 
 /** Shows an error message in the middle of the screen. */
 function ErrorMessage(props: {message?: string}) {
@@ -117,11 +118,16 @@ export class App extends React.Component<RouteComponentProps, {}> {
     hash: string | undefined,
     url: string | undefined,
     gedcom: string | undefined,
+    source: string | undefined,
   ): boolean {
     return (
       !!(hash && hash !== this.state.hash) ||
       !!(url && this.state.url !== url) ||
-      (!!gedcom && !this.state.loading && !this.state.data)
+      (!!gedcom && !this.state.loading && !this.state.data) ||
+      (source === 'wikitree' &&
+        !this.state.loading &&
+        !this.state.data &&
+        !this.state.error)
     );
   }
 
@@ -226,6 +232,7 @@ export class App extends React.Component<RouteComponentProps, {}> {
     const handleCors = getParam('handleCors') !== 'false'; // True by default.
     const standalone = getParam('standalone') !== 'false'; // True by default.
     const view = getParam('view');
+    const source = getParam('source');
 
     const chartTypes = new Map<string | undefined, ChartType>([
       ['relatives', ChartType.Relatives],
@@ -238,9 +245,9 @@ export class App extends React.Component<RouteComponentProps, {}> {
     const images =
       this.props.location.state && this.props.location.state.images;
 
-    if (!url && !hash) {
+    if (!url && !hash && !source) {
       this.props.history.replace({pathname: '/'});
-    } else if (this.isNewData(hash, url, gedcom)) {
+    } else if (this.isNewData(hash, url, gedcom, source)) {
       try {
         // Set loading state.
         this.setState(
@@ -255,9 +262,12 @@ export class App extends React.Component<RouteComponentProps, {}> {
             chartType,
           }),
         );
-        const data = hash
-          ? await loadGedcom(hash, gedcom, images)
-          : await loadFromUrl(url!, handleCors);
+        const data =
+          source === 'wikitree'
+            ? await loadWikiTree(indi!, handleCors)
+            : hash
+            ? await loadGedcom(hash, gedcom, images)
+            : await loadFromUrl(url!, handleCors);
 
         const software = getSoftware(data.gedcom.head);
         analyticsEvent(hash ? 'upload_file_loaded' : 'url_file_loaded', {
diff --git a/src/wikitree.ts b/src/wikitree.ts
new file mode 100644
index 0000000..53e015c
--- /dev/null
+++ b/src/wikitree.ts
@@ -0,0 +1,162 @@
+// WikiTree support is currenlty implemented only as proof of concept.
+// It works for a specific id (12082793) and few others.
+
+import md5 from 'md5';
+import {loadGedcom} from './load_data';
+
+interface GetAncestorsRequest {
+  action: 'getAncestors';
+  key: string;
+  fields: string;
+}
+
+interface GetRelatives {
+  action: 'getRelatives';
+  keys: string;
+  getChildren?: true;
+  getSpouses?: true;
+}
+
+type WikiTreeRequest = GetAncestorsRequest | GetRelatives;
+
+async function wikiTreeGet(request: WikiTreeRequest, handleCors: boolean) {
+  const requestData = new FormData();
+  requestData.append('format', 'json');
+  for (const key in request) {
+    requestData.append(key, request[key]);
+  }
+  const apiUrl = handleCors
+    ? 'https://cors-anywhere.herokuapp.com/https://apps.wikitree.com/api.php'
+    : 'https://apps.wikitree.com/api.php';
+  const response = await window.fetch(apiUrl, {
+    method: 'POST',
+    body: requestData,
+  });
+  const responseBody = await response.text();
+  return JSON.parse(responseBody);
+}
+
+function getFamilyId(id1: number, id2: number) {
+  if (id2 > id1) {
+    return `${id1}_${id2}`;
+  }
+  return `${id2}_${id1}`;
+}
+
+export async function loadWikiTree(id: string, handleCors: boolean) {
+  const firstRelativesData = await wikiTreeGet(
+    {
+      action: 'getRelatives',
+      keys: id,
+      getChildren: true,
+      getSpouses: true,
+    },
+    handleCors,
+  );
+
+  const spouseIds = Object.values(
+    firstRelativesData[0].items[0].person.Spouses,
+  ).map((s: any) => s.Id);
+
+  const everyone: any[] = [];
+
+  [id].concat(spouseIds).forEach(async (personId) => {
+    const ancestorsData = await wikiTreeGet(
+      {
+        action: 'getAncestors',
+        key: personId,
+        fields: '*',
+      },
+      handleCors,
+    );
+    const ancestors = ancestorsData[0].ancestors;
+    ancestors.forEach((a: any) => everyone.push(a));
+  });
+
+  let toFetch = [id];
+
+  while (toFetch.length > 0) {
+    const relativesData = await wikiTreeGet(
+      {
+        action: 'getRelatives',
+        keys: toFetch.join(','),
+        getChildren: true,
+        getSpouses: true,
+      },
+      handleCors,
+    );
+    const people = relativesData[0].items.map((x: any) => x.person);
+    toFetch = [];
+    people.forEach((person: any) => {
+      everyone.push(person);
+      const spouses = Object.values(person.Spouses);
+      spouses.forEach((s) => everyone.push(s));
+      const children = Object.values(person.Children);
+      const childrenKeys = (children as any[]).map((c) => c.Name);
+      childrenKeys.forEach((k) => toFetch.push(k));
+    });
+  }
+
+  // Map from person id to the set of families where they are a spouse.
+  const families = new Map<number, Set<string>>();
+  const children = new Map<string, Set<number>>();
+  const spouses = new Map<string, {wife?: number; husband?: number}>();
+  function getSet<K, V>(map: Map<K, Set<V>>, id: K): Set<V> {
+    const set = map.get(id);
+    if (set) {
+      return set;
+    }
+    const newSet = new Set<V>();
+    map.set(id, newSet);
+    return newSet;
+  }
+
+  everyone.forEach((person: any) => {
+    if (person.Mother || person.Father) {
+      const famId = getFamilyId(person.Mother, person.Father);
+      getSet(families, person.Mother).add(famId);
+      getSet(families, person.Father).add(famId);
+      getSet(children, famId).add(person.Id);
+      spouses.set(famId, {
+        wife: person.Mother || undefined,
+        husband: person.Father || undefined,
+      });
+    }
+  });
+
+  const gedcomLines: string[] = ['0 HEAD'];
+  const converted = new Set<number>();
+  everyone.forEach((person: any) => {
+    if (converted.has(person.Id)) {
+      return;
+    }
+    converted.add(person.Id);
+    gedcomLines.push(`0 @${person.Id}@ INDI`);
+    gedcomLines.push(`1 NAME ${person.FirstName} /${person.LastNameAtBirth}/`);
+    if (person.Mother || person.Father) {
+      gedcomLines.push(`1 FAMC @${getFamilyId(person.Mother, person.Father)}@`);
+    }
+    // TODO: add to spouses map for each spouse.
+    getSet(families, person.Id).forEach((famId) =>
+      gedcomLines.push(`1 FAMS @${famId}@`),
+    );
+  });
+
+  spouses.forEach((value, key) => {
+    gedcomLines.push(`0 @${key}@ FAM`);
+    if (value.wife) {
+      gedcomLines.push(`1 WIFE @${value.wife}@`);
+    }
+    if (value.husband) {
+      gedcomLines.push(`1 HUSB @${value.husband}@`);
+    }
+    getSet(children, key).forEach((child) => {
+      gedcomLines.push(`1 CHIL @${child}@`);
+    });
+  });
+  gedcomLines.push('0 TRLR');
+  const gedcom = gedcomLines.join('\n');
+
+  const hash = md5(gedcom);
+  return await loadGedcom(hash, gedcom);
+}