#include <bits/stdc++.h>
#define ll long long
using namespace std;

const int N = 1e5 + 50;

int T = 1;
int n;
ll a[N], d[70];

void add (ll x) {
    for (int i = 63; i >= 0; i --) {
        if (x >> i & 1) {
            if (d[i]) x ^= d[i];
            else {
                d[i] = x;
                break;
            }
        }
    }
}

ll ask_max () {
    ll ans = 0;
    for (int i = 63; i >= 0; i --) 
        if ((ans ^ d[i]) > ans) 
            ans ^= d[i];
    return ans;
}

void solve () {
    scanf ("%d", &n);
    for (int i = 1; i <= n; i ++) scanf ("%lld", &a[i]);
    memset (d, 0, sizeof (d));
    for (int i = 1; i <= n; i ++) add (a[i]);
    printf("%lld\n", ask_max ());
}

int main() {
    // freopen ("in.in", "r", stdin);
    // freopen ("out.out", "w", stdout);
    scanf ("%d", &T);
    while (T --) {
        solve ();
    }
    return 0;
}